Fibromyalgia, also called fibromyalgia syndrome (FMS), is a long-term condition that causes pain all over the body. As well as widespread pain, people with fibromyalgia may also have: increased sensitivity to painextreme tiredness (fatigue)muscle stiffnessdifficulty sleepingproblems with mental processes (known as "fibro-fog"), such as problems with memory and concentration headaches irritable bowel syndrome (IBS) – a digestive condition that causes stomach pain and bloating