I agree with Wilfred. My wife has had limited shoulder range since she was 17, due to surgery, and I've managed to damage (but not tear) the rotor cuffs in both of my shoulders (once getting a case of beer out of a car). We were both given lengths of surgical tubing by doctors specializing in sports medicine. She pulls hers straight out from the body and out to the side, both high, middle and low heights (the tubing is fastened to a door or some other solidly anchored point). I hold one end in my right hand and rotate my left arm to the side while holding the elbow against my side.

We were both told not to go beyond a "stretching" feeling -- and if it hurt to stop right away. We have to do ten reps as often each day as we can.

This doesn't hurt after a while, and your range of motion gradually returns. Massage also helps.