Do endurance training of your back muscles. I like to train with elastic resistance cables. Keep your shoulder blades together and elbows by your side and anchor the bands at the middle of the door. Face the anchor and walk straight backwards. External rotations with a lightweight elastic cable can strengthen the rotator cuff with pretty low risk, although for both exercises you should not do too much too fast. Improving posture while not being tense during the day can also help. Finally, avoid static positions during the day. Sitting on a chair with a back can make this worse compared to something like a soul seat or an exercise ball.