I also have rotator cuff issues. I have a trainer at the YMCA I go to who is working with me on the issues. There are some exercises that can help with rotator cuff issues.
I took glucosamine/Chondroitin 2 years ago as recommended by an orthopedic surgeon (I had knee problems at that time). It does raise blood sugars and sometimes quite dramatically. My primary physician (who was also diabetic) at the time took me off it because he said it can raise sugar levels. He also said that each person is different so others might not have this problem.
Here is what happened to me: before taking the glucosamine/chondroitin my bs reading was 110 at 1 hour after it was 150, at 2 hours it was over 200! Additionally, it did nothing to help me
As each person is different please make sure to test extra if you take it.