Did you go to a sports medicine specialist? I had some major instability problems a few years ago that ended up requiring surgery. The longer I waited to treat the problem the worse it got. At first, I went to a regular orthopedic specialist and got nowhere. "Regular" doctors love to take x-rays and seem to use it as the only diagnostic tool, which to me, is kind of strange. No mention was made to me of soft tissue damage, except for the standard, cookie-cutter diagnosis of possible rotator cuff tendonits. The problem is that athletes are very talented at finding creative ways to damage the shoulder joint, whereas rotator cuff injuries are quite common among the sedentary.
I researched and found the best shoulder specialist in the state of Colorado (I no longer have access because of my insurance) and finally got the problem properly diagnosed- nobody else could seem to even read an MRI- no joke! Find someone who not only knows what they are doing but cares about getting athletes back into "the game". It's amazing what a difference this had made to me.
It's also amazing how either uniformed or lazy some doctors can be. The temptation is to write off a patient as having rotator cuff tendonitis, which is a problem that can result from having other joint problems. I'm no expert but the shoulder is a very complicated joint.
I just had a 1st degree separation in my "good" shoulder from dh mountain biking, and plan to try the halfpipe on my board this year, so hopefully I won't need to heed my own advice.
Good luck, and I hope you find a way to heal!