Causes of Pain

The possible causes depend greatly on the exact type and location of pain. Nevertheless, some of the common possible causes of pain (overall) may include these categories:

Traumatic Injury: Often the cause of pain is trauma or injury, such as:

Also possible causes of pain include:

Nerve Conditions: Various nerve conditions can cause nerve pain or pain-like sensations such as paresthesias:

Systemic Disorders: Various types of systemic problems may cause pain:

This is only an abbreviated list. A list of all the causes of all the types of pain is not realistic. Review the causes of the more specific types of pain.

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Back to: « Pain

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Inflammation and Pain

The link between the nervous and immune systems also is important. Cytokines, a group of proteins found in the nervous system, are also part of the immune system—the body's shield for fighting off disease and responding to tissue injury. Cytokines can trigger pain by promoting inflammation, even in the absence of injury or damage. After trauma, cytokine levels rise in the brain and spinal cord and at the site where the injury occurred. Improvements in our understanding of the precise role of cytokines in producing pain may lead to new classes of drugs that can block the action of these substances to produce analgesia.

Source: NINDS (NIH)1

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The A to Z of Pain

Hundreds of pain syndromes or disorders make up the spectrum of pain. There are the most benign, fleeting sensations of pain, such as a pin prick. There is the pain of childbirth, the pain of a heart attack, and the pain that sometimes follows amputation of a limb. There is also pain accompanying cancer and the pain that follows severe trauma, such as that associated with head and spinal cord injuries. A sampling of common pain syndromes follows, listed alphabetically.

Source: NINDS (NIH)2

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20 painful health conditions

Here are 20 health conditions known to cause pain so disabling that they can prevent you performing daily tasks.

They're not ranked in any particular order.

Source: NHS Choices UK3

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Shingles: Shingles typically appears as a rash or crop of blisters on one side of your body, often around the waistline.

The pain of shingles tends to be burning or tingling, and often affects only one side of your body. You may feel stabs of pain when someone simply brushes lightly against the affected skin or a breeze wafts over it.

Some people who have had shingles can develop a persistent pain called post-herpetic neuralgia.

Read more about shingles and the shingles vaccine.

Source: NHS Choices UK4

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Cluster headaches: Cluster headaches

Cluster headaches are excruciating attacks of pain on one side of the head, often felt around the eye.

They begin quickly and without warning. The pain is very severe, and is often described as a sharp, burning or piercing sensation.

People often feel restless and agitated during an attack because the pain is so intense, and they may react by rocking, pacing, or banging their head against the wall.

Read more about cluster headaches.

Source: NHS Choices UK5

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Frozen shoulder: Frozen shoulder

This condition not only is extremely painful but also can last for several years if not properly treated.

In frozen shoulder, the joint becomes so tight and stiff that it's virtually impossible to carry out simple movements, such as raising your arm. Daily activities like taking off a T-shirt, lifting a kettle, putting on a coat or even combing your hair become an ordeal.

It's not clear what causes frozen shoulder, but it can happen after a shoulder or arm injury, and is more common in people with diabetes.

Read more about frozen shoulder.

Source: NHS Choices UK6

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Fractures: Broken bones

A broken or cracked bone is known as a fracture. Common examples are a broken ankle, broken hip, broken arm or broken nose.

If the break is small, it's possible you might not feel any pain at all but, usually, a broken bone really hurts, especially when you try to move it. The pain is often described as feeling like a deep ache.

Broken bones can heal by themselves, but they may need to be lined up and fixed in position so they set properly. As a general rule, the older you are and the bigger the bone that's broken, the longer it will take to heal.

Source: NHS Choices UK7

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Complex regional pain syndrome: Complex regional pain syndrome (CRPS)

CRPS is a severe, long-lasting pain that can appear shortly after an injury, such as a fracture, burn or cut.

The burning pain of CRPS is continuous and intense, and often completely disproportionate to the severity of the original injury.

The pain is usually confined to the previously injured limb but can sometimes spread to other parts of the body.

The skin of the affected body part can become so sensitive that just a slight touch, bump or even a change in temperature can provoke intense pain.

Read more about CRPS.

Source: NHS Choices UK8

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Heart attack: Heart attack

If you have a heart attack, you usually get a pain in the centre of your chest - often described as a sensation of heaviness, tightness or squeezing - that can be so bad it causes you to collapse.

The pain can feel like really bad indigestion, and sometimes spreads to your jaw, neck, back, arms or stomach.

If you suspect that you or someone else is having a heart attack, call for emergency help immediately.

Find out more about heart attack and read 64-year-old Derek's real-life description of what it feels like to have a heart attack.

Source: NHS Choices UK9

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Slipped disc: Slipped disc

One of the most common causes of back pain is a slipped disc. It's often the result of a twisting or lifting injury. One of the discs in the spine ruptures, and the gel inside leaks out.

Most people with a slipped disc experience sudden and severe lower back pain. It's usually eased by lying down, and often made worse by moving your back, coughing or sneezing. A slipped disc can also cause leg pain.

Read more about slipped disc.

Source: NHS Choices UK10

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Sickle cell disease: Sickle cell disease

A sudden episode of pain, known as a pain crisis, is one of the most common and distressing symptoms of sickle cell disease.

The pain, which usually occurs in the bones and joints, can vary from mild to severe and last for up to seven days.

Some people may have an episode every few weeks, while others may have fewer than one a year.

Read more about sickle cell disease.

Source: NHS Choices UK11

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Arthritis: Arthritis

People with arthritis endure constant and often disabling joint pain, usually in the hips, knees, wrists or fingers. The pain can come on suddenly or over time, and is often linked with muscle aches and stiffness in the joints.

Various different types of arthritis - including rheumatoid arthritis, osteoarthritis and lupus - can cause joint damage.

Read more about arthritis.

Find your local arthritis support services.

Source: NHS Choices UK12

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Migraine: Migraine

A migraine typically feels like an intense headache on one side of the head. The pain is usually a moderate or severe throbbing sensation that gets worse when you move and prevents you from carrying out normal activities.

In some cases, the pain can occur on both sides of your head, and may affect your face or neck.

Migraines can cause vomiting and extreme sensitivity to light and sound. Sometimes, in cases of severe migraines, the best thing to do is find a dark, quiet place to lie down until the pain passes.

Find out more about migraine and read a true-life account of what it's like to have migraine.

Find your local migraine clinic.

Source: NHS Choices UK13

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Sciatica: Sciatica

Sciatica is the name given to an aching pain running down the leg. It's caused when the sciatic nerve - the longest nerve in the body, which stretches from your back to your feet - has been pinched or irritated by damage to the back.

Sciatica is different to general back pain. The pain of sciatica hardly affects your back at all - instead, it radiates out from your lower back, down the buttocks and into one or both of the legs, right down to the calf.

Read more about sciatica.

Source: NHS Choices UK14

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Kidney stones: Kidney stones

Passing a kidney stone can produce a sudden, sharp, cramping pain in your lower back or the side of your abdomen, or occasionally in your groin. The pain may last for minutes or hours, with pain-free intervals in between.

The pain often begins in the middle of the night and can be so severe that those who experience it may feel the need to go to A&E.

Most kidney stones are small enough to pass out in your urine, and the pain disappears once the stone has been passed.

Read more about kidney stones.

Source: NHS Choices UK15

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Acute Appendicitis: Appendicitis

Appendicitis is a painful swelling of the appendix, a finger-like pouch attached to the gut wall. It's most common in children, who typically complain of pain in the middle of their tummy that comes and goes. The pain then shifts to the lower-right side of the tummy and gets worse.

Appendicitis is a medical emergency that usually needs an urgent operation to remove the appendix before it bursts.

Read more about appendicitis.

Watch this animation to learn about the causes and treatment of appendicitis.

Source: NHS Choices UK16

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Trigeminal neuralgia: Trigeminal neuralgia

Trigeminal neuralgia, also known as Fothergill's disease, involves bouts of severe pain on one side of the face that comes and goes unpredictably in sudden attacks.

Some people say the pain feels like an electric shock shooting through the face, while others describe intense sensations of burning or stabbing.

Read more about trigeminal neuralgia.

Source: NHS Choices UK17

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Acute pancreatitis: Acute pancreatitis

Acute pancreatitis is the swelling of the pancreas, a banana-sized organ that's part of the digestive system. The most common symptom is severe abdominal pain that appears suddenly.

This dull aching pain often gets steadily worse and can travel along your back or below your left shoulder blade.

Eating or drinking, especially fatty foods, may also make you feel worse very quickly. Leaning forward or curling into a ball may help to relieve the pain, but lying flat on your back often increases it.

Read more about pancreatitis.

Source: NHS Choices UK18

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Gout: Gout

Gout is where swelling and severe pain develops in a joint, often the base of the big toe, to the point where moving or even touching the toe can be agony. It's one of the most painful forms of arthritis.

During an attack of gout, the joint starts to ache, before swelling up and becoming red, hot and extremely painful. Attacks can last between 1 and 10 days.

Read more about gout.

Source: NHS Choices UK19

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Endometriosis: Endometriosis

Endometriosis is the spread of womb cells outside the womb, mainly around the lower abdomen.

While some women with endometriosis have no symptoms at all, others have lots of pain, including pelvic pain, period pain, and pain during and after sex.

Read more about endometriosis.

Source: NHS Choices UK20

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Stomach ulcer: Stomach ulcer

An ulcer is a sore or hole that forms in the lining of the stomach. A stomach ulcer can cause a burning pain in the abdomen, often between meals.

An untreated ulcer can burn through the stomach wall, letting digestive juices and food leak into the abdominal cavity, causing disabling pain.

This is called a perforated ulcer and is a medical emergency that usually needs to be operated on immediately.

Read more about stomach ulcer.

Source: NHS Choices UK21

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Fibromyalgia: Fibromyalgia

Fibromyalgia can cause aches and pains all over the body, typically in the back of the neck, shoulders, lower back, hips, shins, elbows and knees. People with fibromyalgia often say they ache all over.

Quite often, the pain and stiffness is worse in the morning, and you may have more pain in muscle groups that you use repetitively.

Read more about fibromyalgia.

Source: NHS Choices UK22

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Post-surgical pain: Pain after surgery

It's common to have some pain after surgery, though the intensity of the pain will vary according to the type of operation.

But too much pain after surgery is not a good thing, and you should never feel you have to "tough it out".

There are lots of effective painkillers on offer to keep your pain after surgery under control. In addition to making you more comfortable, well-controlled pain will help you get better faster and prevent long-term problems.

Read more about what happens after having an operation.

Source: NHS Choices UK23

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Post-herpetic neuralgia: In post-herpetic neuralgia, the virus causes inflammation of the nerves under the skin of the affected area. Neuralgia is a medical term for pain resulting from nerve inflammation or damage.

Source: NHS Choices UK24

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Some causes may include:25 Causes of Pain:

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Some more causes may include:26 Causes of Pain:

  • Hereditary Painful Callosities

Causes List for Pain

List of possible causes of Pain or similar symptoms may include:27

... Full Causes List for Pain »

Physiologic Causes of Pain

Anatomy of Pain

Pain signals from the head and face directly enter the brain stem where they join the pain pathways that travel from the spinal cord to the brain. One central place these signals travel to is the thalamus. The thalamus is a relay station that distributes sensory signals to many other brain regions—including the anterior cingulate cortex, somatosensory cortex, insular cortex, and prefrontal cortex. These cortical brain regions process the nociceptive (pain causing or reacting to pain) information from the body and generate the complex experience of pain. This pain experience has multiple components that include the: 1) sensory-discriminative aspect which helps us localize where on our body the injury occurs, 2) affective-motivational aspect which conveys just how unpleasant the experience is and the 3) cognitive-evaluative which involves thoughtful planning on what to do to get away from the pain. Many of these characteristics of pain have been associated with specific brain systems, although much remains to be learned. Additionally, researchers have found that many of the brain systems involved with the experience of pain overlap with the experience of basic emotions. Consequently, when people experience negative emotions (e.g. fear, anxiety, anger), the same brain systems responsible for these emotions also amplify the experience of pain.

Fortunately, there are systems in the brain that help to dampen or decrease pain. Descending signals from the brain are sent back to the spinal cord and can inhibit the intensity of incoming nociceptive signals, thereby reducing the pain experience.

Source: NINDS (NIH)28

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Neurochemistry of Pain

This complicated process by which we perceive pain involves intricate connections among multifaceted brain regions. The nervous system uses a set of chemicals, called neurotransmitters, to communicate between neurons within and across these stations in the pain pathway. These chemicals are released by neurons in tiny packets (vesicles) into the space between two cells. When they reach their target cell, they bind to special proteins on the surface of the cells called receptors. The transmitter then activates the receptor, which functions much like a gate. The gate will either close to block (inhibitory receptor) the signal or open to send (excitatory receptor) the signal along to the next station.

There are many different neurotransmitters in the human body and they play a role in normal function as well as in disease. In the case of nociception and pain, they act in various combinations at all levels of the nervous system to transmit and modify signals generated by noxious stimuli.

One excitatory neurotransmitter of special interest to pain researchers is glutamate, which plays a major role in nervous system function and in pain pathophysiology. The modulation of glutamate neurotransmission is complex, but it plays a key role in heightening the sensitivity to pain through increased responsiveness of excitatory receptors in the spinal cord dorsal horn and in the brain. This is part of a process called central sensitization (see below) and contributes to making pain persist. A great deal of attention has been given to developing molecules/drugs that block certain receptors for glutamate for their potential in reducing pain.

Unlike glutamate, GABA (or gamma-aminobutyric acid) is predominately an inhibitory neurotransmitter in that it generally decreases or blocks the activity of neurons. Most of what we know of its role in pain is related to its function in inhibiting spinal cord neurons from transmitting pain signals and therefore dampening pain. Chemicals that are similar to GABA have been explored as possible analgesics, but because GABA is so widespread in the nervous system it is difficult to make a GABA-like drug without affecting other nervous system functions. As we learn more about the specific roles of GABA receptors, drug development may be accelerated.

Norepinephrine and serotonin are neurotransmitters used by the descending pain pathways from the brain stem to dampen the incoming signals from painful stimuli from the site of the injury or inflammation. Drugs that modulate the activity of these transmitters, such as some antidepressants, are effective in treating some chronic pain conditions, likely by enhancing the availability of the transmitters through a recycling and reuse process. Serotonin receptors also are present on the nerves that supply the surface of the brain involved in migraines, and their modulation by a class of drugs called “triptans” is effective in acutely treating migraine.

The opioids are another important class of neurotransmitters that are involved in pain control, as well as pleasure and addiction. Their receptors are found throughout the body and can be activated by endogenous (produced by our bodies) opioid peptides that are released by neurons in the brain. The enkephalins, dynorphins, and endorphins are some of the body’s own natural pain killers. They may be more familiar for the role of endorphins in the feeling of well-being during exercise—the runner’s high. Opioid receptors also can be activated by morphine, which mimics the effect of our endogenous opioids. Morphine is a natural product and like similar synthetic opioids, is a very potent, but potentially addictive pain killer that is used broadly for severe acute and chronic pain management. Together the opioids provide effective pain relief for many people with pain. Other peptides also transmit neuronal signals and play a role in pain responses. Scientists have shown that mice bred experimentally to lack a gene for two peptides, called tachykinins-neurokinin A and substance P, have a reduced response to severe pain. When exposed to mild pain, these mice react in the same way as mice that carry the missing gene. But when exposed to more severe pain, the mice exhibit a reduced pain response. This suggests that the two peptides are involved in the perception of pain sensations, especially moderate-to-severe pain.

Source: NINDS (NIH)29

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  1. Source: NINDS (NIH): disorders/ chronic_pain/ detail_chronic_pain.htm
  2. ibid.
  3. Source: NHS Choices UK: Livewell/ Pain/ Pages/ 20-painful-conditions.aspx
  4. ibid.
  5. ibid.
  6. ibid.
  7. ibid.
  8. ibid.
  9. ibid.
  10. ibid.
  11. ibid.
  12. ibid.
  13. ibid.
  14. ibid.
  15. ibid.
  16. ibid.
  17. ibid.
  18. ibid.
  19. ibid.
  20. ibid.
  21. ibid.
  22. ibid.
  23. ibid.
  24. Source: NHS Choices UK: conditions/ post-herpetic-neuralgia/ 
  25. Source: Human Phenotype Ontology
  26. ibid.
  27. Source: Algorithmically Generated List
  28. Source: NINDS (NIH): disorders/ chronic_pain/ detail_chronic_pain.htm
  29. ibid.

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.