For two years ive been having pain and muscle weakness in my legs.the pain starts when i sit. sometimes along with the pain i get nausea and headaches. i recently found out that my cpk is 546. what could be causing the leg pain?

Myositis : Myositis, or muscle inflammation, may have any numbers or causes. The first place to look is whether the muscle inflammation is due to a medicine or supplements that you are taking. If that is not the case, polymyositis and dermatomyositis, are two diseases caused by a faulty immune system that causes the body's immune system to attack the muscles. I would start with your primary care physician.