Fibromyalgia is a chronic pain disorder that causes widespread pain throughout the body, as well as sleep issues, exhaustion, and, in many cases, emotional and mental distress. Fibromyalgia patients may be more sensitive to pain than others. This is referred to as abnormal pain perception. In the United States, approximately 4 million adults suffer from fibromyalgia, accounting for 2% of the adult population. Fibromyalgia has no known cause, but it is treatable and manageable.