The exact cause of fibromyalgia is unknown but it is thought there are a number of factors in play, with a mix of physical, neurological and psychological factors. The following are among the factors that are thought to contribute to the condition:

Chemical imbalance

Changes in hormone levels are thought to play a part in the development of the disease and research has found that people with fibromyalgia have abnormally low levels of the hormones serotonin, noradrenaline and dopamine.

According to the NHS levels of these hormones may be a key factor in the cause of fibromyalgia as they're important in regulating things such as:

Your response to stressful situations

These hormones also play a role in processing pain messages sent by the nerves. Increasing the hormone levels with medication can disrupt these signals.

Some researchers have also suggested that changes in the levels of some other hormones, such as cortisol (released when the body is under stress), may contribute to fibromyalgia

Genetics

It is not proven that genetics play a part in your susceptibility to the disease, but it does seem to run in families. The possibility that it is linked to genetics may explain why some people develop the condition after a some kid of trigger. Your parents may also pass on genes that make you more sensitive to pain

A stressful event

It is thought that the condition can be triggered by an event that might cause you stress, wither physically, emotionally or both, such as a car accident, an operation or the loss of a loved one.

People with fibromyalgia often report that their symptoms started after an illness or accident, or following a period of emotional stress and anxiety.

Sleep disturbance

In an experiment where healthy volunteers were woken repeatedly during a period of deep sleep, a number of them developed the typical signs and symptoms of fibromyalgia and it is possible that disturbed sleep patterns may be a cause of fibromyalgia, rather than just a symptom.

Abnormal pain messages

One of the main theories is that people with fibromyalgia have developed changes in the way the central nervous system processes pain messages carried around the body. This could be due to changes to chemicals in the nervous system.

Changes in the way the nervous system works may explain why fibromyalgia results in constant feelings of, and extreme sensitivity to, pain.