A lot of shoulder pain can be easily fixed by merely strengthening the rotator cuff. This is accomplished with the following exercise:
Lay on your side and make sure that your body is perpendicular to the surface upon which you’re laying. Grab a 5 lb dumbbell or lighter — the rotator cuff is not designed to carry heavy weight — and keep your arm bent at a right angle with your elbow pinned into your side. Rotate the dumbbell up a few inches higher than parallel to the ground and then all the way down until the dumbbell is about an inch or two from your body, then rotate it up again. Do this exercise slowly so that other muscle groups don’t take over. The last half-inch or so of the rotation at the top of the movement is where the rotator cuff works the hardest, so don’t stop short until you’ve rotated your arm to the proper height. But of course, always be mindful that your arm is bent at an exact right angle and that your elbow is pinned into your side.
Do this exercise every other day for 3 sets of 12-15 reps each set, and again, do your reps slowly.
For additional help with shoulder pain, do some back strengthening exercises so that your shoulders are naturally drawn back, giving you proper posture and saving you from becoming a hunchback when you’re older!