Symptoms sometimes begin after a physical trauma, surgery, infection or significant psychological stress. In other cases, symptoms gradually accumulate over time with no apparent single triggering event.

Symptoms of fibromyalgia include:

• Widespread pain. The pain associated with fibromyalgia often is described as a constant dull ache of muscles and joints.
• Fatigue. People with fibromyalgia often have difficulty sleeping and awaken tired, even after sleeping for long periods of time. Sleep is often disrupted by pain, and many patients with fibromyalgia have other sleep disorders, such as restless legs syndrome and sleep apnea.
• Cognitive difficulties. Many people with this condition report “brain fog”, a mental condition which impairs the ability to focus, pay attention and concentrate on mental tasks.
• Gastrointestinal complaints. Many people with fibromyalgia also have gastrointestinal problems such as constipation, diarrhea, irritable bowel sydrome with abdominal cramping and/or small intestinal bacterial overgrowth.
• Other health conditions. Many people who have fibromyalgia also may experience depression, anxiety, headaches, and sleeping disorders.

Doctors don’t know what causes fibromyalgia, but it most likely involves a variety of factors working together. Some of the potential causative factors that have been studied include:

• Central nervous system problems.  Several symptoms reported by fibromyalgia patients—including amplified pain, impaired concentration, attention, and memory and fatigue—suggest that the central nervous system may be involved in the pathophysiology of the syndrome. Researchers have investigated a central nervous system (CNS) link to fibromyalgia but have been unable to identify a causal link.
• Chronic pathogenic infections.  Some people develop fibromyalgia after suffering from a viral, bacterial or other pathogenic infection.  Therefore, some researchers believe that certain viruses or other pathogens might trigger the disorder.  Suspicious viruses include Epstein-Barr virus (EBV), human herpes virus 6 (HHV-6) and other viruses.  Some bacterial species that can become chronic and have been associated with fatigue and other symptoms are Borrelia, Bartonella and Babesia.
• Toxicity and compromised hepatic detoxification. Some research suggests that toxic exposures to environmental chemicals and heavy metals may play a role in the development of fibromyalgia.  Studies suggest an association with increased levels of heavy metals and other toxins in patients with fibromyalgia and improvement in symptoms when the elimination of these toxins is supported via hepatic detoxification pathways.
• Mitochondrial dysfunction.  The mitochondria are the “power-houses” of the cells which provide the energy needed to fuel cellular processes and efficient ATP production is required for tissue and organ health.  However, the mitochondria are very vulnerable to oxidative stress which can impair mitochondrial production of ATP.  Impaired ATP production by the mitochondria has been associated with fibromyalgia and is believed to be due to excessive oxidative stress and insufficient antioxidant enzyme activity.
• Immune system dysfunction. The immune system of people with fibromyalgia appears to be dysfunctional.  There is often chronic inflammation as a result of other problems such as chronic infections, compromised hepatic detoxification, oxidative stress and mitochondrial dysfunction.
• Hormonal imbalances. Hormonal imbalances are common in people with fibromyalgia, particularly with the hypothalamic-pituitary-adrenal (H-P-A) axis.  The adrenal glands are responsible for producing corticosteroids, such as cortisol, which are important in regulating immune responses, glucose levels and the sleep-wake cycle, among other functions.