I've just quickly skimmed this thread; I apologize if I've missed some things. A couple questions that could help direct treatment:

1) Do you have altered sensation (numbness and tingling), and if so, where specifically in the arm?
2) Has anyone been checked for thoracic outlet syndrome? I see this quite often.

You should be aware that imaging is rarely a good way to diagnose an issue. See Are your x-ray and MRI results helpful or harmful? - YouTube