Fibromyalgia is a chronic disorder that causes muscle pain and fatigue. People with fibromyalgia have “tender points” on the body. These points hurt when pressure is put on them. The patients may also have other symptoms, such as trouble sleeping, stiffness, headaches, tingling or numbness in hands and feet or problems with thinking and memory (sometimes called “fibro fog”). It is not yet known what causes fibromyalgia.