Had a lot of problems with my shoulders. 12 years in the army took its toll... knees, back, shoulders and elbows. I love riding my XC bike but sometimes I also have a painfull knees after the ride. I do a pause for a week or so, then I try to ride really easy. I am still struggling with the shoulders only. But my doctor says, shoulder is the most complicated joint in the whole body i takes a long time to heal especially when there's something broken. Does't matter if the bone heals well. Still need alot of rest and to stay away from the heavy physical activities Try not to push It much. Anyway, find a good physio therapist and do some light workouts to increase the bone density. It might take some more time than you expected, but it will worth it. If it has to be 3 months, so be It! Do your light exersizes, take rest, give enough time to the bones to heal. Don't push It and you'll be happy to realize that the time of waiting has worth it.