Hi Thank you for asking HCM I have gone through your query. Rotator cuff is responsible for different axis of movements in shoulder. Rotator cuff tendinitis or tear can give such symptoms you mention. There are four rotator cuff muscles. So it can be related to any of that. A physical examination by an orthopedician will give clue for this and MRI will be needed to confirm it in presence of positive signs. In case of moderate to severe tear arthroscopic correction can be done to get your problem solved. If mild then physical therapy and modification of exercises you do can make you better. Hope this may help you. Let me know if anything not clear. Thanks.