Recommendation from a physical therapist:

Be sure to strengthen your roator cuff as much as possible. I would recommend getting some theraband from your local medical supply store. It is really cheap. It comes in different thickness/colors to vary the resistance. I would recommend using themedium thicknesstheraband ( I believe it is red ). Focus on shoulder external rotation ( rotating the shoulder outward with your elbow against your side ) and shoulder abduction ( bringing the arm up at your side ).

I also have had rotator cuff problems. Using theraband has really helped my archery. I hope this helps. If you have any specific questions or needs please let me know.