Fibromyalgia

I had a partial knee replacement in Nov 2010. Still cannot straighten knee when I walk. Going to pt for 8 wks now. Still have pain. I also was diagnosed with fibromyalgia by my OS. He touched a muscle going down from knee to ankle on both legs which was tender to the touch and said I have fm. My muscles are sore to the touch on my lower legs, hips, arms. I was a couch potato for about 2 years because of my hurting knees. I'm thinking my muscles are just sore from no activity. I did notice this morning that the outside of my leg was red. I also have tingling and my right arm feels heavy. Could it be a pinched nerve? What do I do about my knee and also what doctor can I go to to make sure I have fibromyalgia or could it be something else. HELP.