while this could be something as simple as a shoulder impingement, it could also be something a bit more serious, like a pinched nerve or blood clot, both of which require medical attention... and can be very dangerous. You need to seek professional medical attention, as only a doctor or specialist should diagnose anything like this, and only AFTER they have done a full examination. Please seek medical attention. Good luck, I truly hope that you willl be pain free soon.

-Sara