I’m dealing with the exact same symptoms you describe. You need to get a professional diagnosis, including xrays and possibly an MRI, because several things can cause similar symptoms. I didn’t have a rotator cuff tear; didn’t think I did because I’ve always been careful not to overbow myself and to draw the bow slowly, not jerk it. But I do have a build-up of calcium in my shoulder muscles that causes friction against another part of the shoulder when I draw the bow. They are working at reducing the calcium several different ways, and I have a regimen of exercises from the physical therapist. 45 years as a CPA have left me with slumped shoulders, and the exercises are to strengthen the parts of my back and shoulder that have stretched out to get me in a better posture and provide more room for the affected parts of the shoulder to move around each other. I was skeptical about the exercises at first: why should more exercises help what exercise probably caused? The amazing thing is that now that I know how to do the exercises, if my shoulder starts hurting, I can do the exercises and by the time I’m done it doesn’t hurt anymore! And it doesn’t hurt later!
At one point, it got so bad that I couldn’t raise my right arm any higher than my waist. After working with the docs, I’m now back on a regular shooting schedule and feel little or no pain. In any event, look at Arne Moe’s description of the rotational draw. Really doing that exactly as he describes helped me as much as anything else.