Pain within left shoulder blade. 3 years ongoing. relieved with pressure, ice, and percocet. with sleep left arm goes numb. what could it be?

SeveralPossibilities: One possibility is Thoracic Outlet Syndrome which involves compression of nerves, veins, and arteries and can cause persistent pain with positional numbness. It is often due to prior trauma. I would recommend seeing a clinician who can perform specific physical exam maneuvers and potentially other tests to confirm a diagnosis, and then initiate appropriate treatment.