I had an injury when I was 13, which riped a few tendons in my right shoulder. It has not been a problem, until I started  lying on the shoulder for  some time, during sleep.
Reading some of the training routine for rehab of the shoulders and they made up of
1. Because they made up of cartilage, warm up thoroughly before you do any stretch.
2. If you have had problems with your shoulders, get a range of movement test by a physio.
3. The above will then be able to select exercise that you can do and the ones that you should not do under any circumstance.
Look after those shoulders, because this will effect your swing path.