What are the causes of an achey pain in my legs and arms?

Not fibromyalgia.: But, whatever is is, not enough info given. When does it occur; how long has it been present; what makes it worse; where in your arms and legs; does it occur at night, or only with activity. You need to answer these yourself and see your doctor with these answers in your head! than you can be properly evaluated for a long list of potential diagnoses!