All of this will probably help you
1. Drop all pressing movements
2. Do lots of horizontal pulling (rowing.... except NOT upright rows)
3. Strengthen ONLY your external rotators... ignore internal rotators
4. foam roll thoracic spine
5. Ice after any exercise/swelling
6. Band dislocates & wall slides (youtube these)
7. Lots of massage/tennis balling/etc. from the scapulae to the anterior shoulders.
8. Stretch chest and lats. A LOT.
9. Fish oil for anti-inflammatory, joint supps if you need any (sections 4&5 describe these here):
Here's a good set of vids on scapular mobility and stability:
all links wfs