The sharp pains need to be evaluated. If this is associated with a heaviness in the chest, difficulty breathing,
sweatingSweating
Sweating - absent, nausea, or chest pain then I think
cardiacCardiac catheterization
Cardiac tamponade
Left heart ventricular angiography disease should be excluded. If this is a neurologic problem it may be a problem in your spine or in one of the nerves of the arm. A neurologist can evaluate you and help determine which is likely. Then the appropriate testing can be performed. Good luck.