What Causes Fibromyalgia? Fibromyalgia (FM) is a chronic illness involving widespread sensitivity and pain within the whole musculoskeletal system. In addition to pain, patients report disturbed mood, sleep, fatigue, cognitive fog, vertigo, and numbness/ tingling in the extremities. Other disorders could include emotional ailments, TMJ pain, dysfunction, and irritable bowel syndrome. Fibromyalgia is a common