A easy stretch for your shoulder that you can try today is the towel shoulder rotation stretch. In my clinic we call it the "hand behind the back" stretch. It is a combination of internal rotation, extension, and adduction of the shoulder joint and it can be effective to gain range of motion in the shoulder after rotator cuff surgery or if you have a frozen shoulder.
The stretch is easy to peroform with a towel or a belt. Simply place the towel over your shoulder so it hangs down your back. Then grab the end of the towel that is hanging by your back, and pull your arm across and up your back. You should feel a slight stretch in the front or side of your shoulder.
Be sure to check with your doctor or physical therapist before performing any exercise program.