I took a very severe fall onto my shoulder 9 months ago, and believe I impinged a nerve. That resulted in pain in my shoulder that eminated down my arm into my funny bone , and on into my wrist/hand. It seemed to very slowly heal, although never disappeared completely. The other day, it seemed to come back to where it was many months ago. Will an impingement ever heal completely?.....does hot or cold therapy help?....should I have an MRI?