The word fibromyalgia means pain (algia) coming from the muscles (my) and fibrous tissues (fibro) such as tendons and ligaments. Most people with fibromyalgia also have other symptoms in addition to the pains. Therefore, fibromyalgia is sometimes called fibromyalgia syndrome (FMS). It is a persistent (chronic) condition. Fibromyalgia does not affect the joints, and so is not an arthritis.

The cause of fibromyalgia is not known. However, research has shown that people with fibromyalgia have certain subtle changes in some chemicals in the brain and nervous system. For example, there seems to be a minor change in the level of certain brain chemicals called neurotransmitters. These are the chemicals responsible for transmitting messages between nerves and between brain cells. Research studies have also shown that people with fibromyalgia tend to have an increased amount of a chemical called substance P in the fluid that bathes the brain and spinal cord (the cerebrospinal fluid (CSF)). This substance may be involved in the way pain messages are transmitted.

A current main theory is that people with fibromyalgia have an oversensitivity to pain signals in the brain. This is called central sensitization. This may be due to various minor changes in brain chemicals. What triggers or causes these changes is not known.

There is no cure for fibromyalgia. Treatments of fibromyalgia may include exercise, heated pool therapy and Cognitive Behavioural Therapy. Painkillers such as paracetamol, anti-inflammatory painkillers, e.g. ibuprofen, or stronger painkillers including codeine may help to ease pain. However, they often do not work very well in fibromyalgia. Additionally antidepressants are often helpful for easing pain and improving overall function. They may also help with disturbed sleep. Medicines called pregabalin and gabapentin have also been shown to help some people with fibromyalgia.