I think you need to sort out how much of the problem is shoulder and how much neck; if the tear is in the supraspinatus tendon, then your bicep and forearm pain would not really be linked to that, though very often the bicep tendon is impinged along with the supraspinatus tendon; is grip weakness just on it's own - like dropping paper from b/w fingers or dropping coffee cup? That could be a sign of nerve conduction loss. Pins/needles, burning, shooting pain into the fingers could also be more nerve than shoulder tendon; not an easy thing to sort out sometimes, but i'd get as many opinions as possible before going in for any procedures. Regards.