· Irritable bowel syndrome (IBS) – Constipation, diarrhea, abdominal pain and bloating associated with IBS are common in people with fibromyalgia. Psychological stress and hormonal changes also may be possible causes of fibromyalgia.Seek Medical AdviceWhenever you experience general aching or widespread pain that lasts several months and is accompanied by fatigue, it is time to see your doctor.