It is hard for me to answer your question accurately without evaluating you but I can give you some generally advice which might be of help.
Chest pain which gets exacerbated by position or arm movement is very likely to be non cardiac in nature, which has been what seems to be the results of your physician's evaluation.
Non cardiac etiologies of chest pain include musculoskeletal conditions (likely in your case), lung problems, food pipe related problems etc.
Given the fact that it is the arm movement which bothers your chest, it is certainly likely that this is a rotator cuff injury.
This is not an uncommon problem and a variety of treatment options exist for this condition. I would begin by seeing a primary care physician or a sports medicine doctor or an orthopedic surgeon who will be able to perform testing to accurately diagnose your problem and treat accordingly.
Hope that helps
I have been to a primary care physician he wants me to get a MRI to see if it is a rotator cuff problem.He said a x-ray would'nt show if it was a rotator cuff injury I am just glad that someone finally told me something that sounds good!!!Would an MRI show if it is the rotator cuff?