I have a chronic pain in my left arm. I have gone to doctors and taken a lot of pain killers. I have taken all lab tests and everything is fine. Even a bone density analysys. The pain can't be pinpointed in the arm and it sometimes shifts to my collarbone. Pain is more intense at night. I am a woman, 48 in overall good health. I walk a few miles every other day and I feel much better then. I even had a series of Meticoval intramuscular injections. Pain is still there. The last doctor said it could be fibromyalgia and gave a me prescription (Lyrica) that when researched had more serious side effects than regular pain killers. I did not dare take it. My question is, could this be a pinched nerve? How can I find out? Which specialist could find this out? Thank you.