surgery.
had one done last year, the other in 2 weeks.
They clean out all the frayed and damaged tissue and ligament etc and clean up the surfaces.
IF its worse, they might find minor tears in the tendons and need to reattach those as well, AND they might need to open up a space for the delt and tendon to easily slide over..that means they take off a bit of your clavicle.
They usually do the first thing first, unless they find torn tendons when they do the MRI..then they do both.
recovery is a bitch. weeks/months. I could barely move for a day or so, then over a week it got better quickly, but it was still limited for about 12 weeks. At week 20 i feel as its back to better than bursitis, but i still havent trained as heavy as i ever did..probably never will again.
there you go.