According to U.S. National Library of Medicine at the National Institutes of Health Fibromyalgia is:
a common syndrome in which people experience long-term, body-wide pain and tender points in joints, muscles, tendons, and other soft tissues.
Fibromyalgia has also been linked to fatigue, sleep problems, headaches, depression, anxiety, and other symptoms.
The cause of this disorder is unknown. Although none have been well proven, possible causes or triggers of fibromyalgia include:

Physical or emotional trauma
An abnormal pain response. Areas in the brain that are responsible for pain may react differently in fibromyalgia patients.
Sleep disturbances, which are common in fibromyalgia patients.
An infectious microbe, such as a virus. At this point, no such virus or microbe has been identified.

The following conditions may be seen with fibromyalgia or mimic its symptoms:

Chronic neck or back pain
Chronic fatigue syndrome
Depression
Hypothyroidism
Lyme disease
Sleep disorders

More and more I am seeing clients with these symptoms. In this interview I spend time with EFT Rue Hass talking about her experience with clients who are experiencing symptoms of fibromyalgia. We talk about causes as well things she has seen in her practice that has been helpful for these symptoms