For any form of arthritis I recommend my joint freeing pose series from my book. This is best to do by itself without any other form of exercise for 2 weeks minimum. This can relieve much of the pain. I also mentioned the arthritis diet from Indra Devi, which is a cure. The anti-pitta diet from Ayurvedic diets is recommended as a long-term solution. If you didn’t get that I can send it to you.
For rotator cuff problems again I recommend Joint Freeing series do the entire series and the motions for the shoulder do twice as many as others. In general it is a vata imbalance and needs gentle but persistent activity. Stretches can irritate it. I do not recommend trying to stretch out the shortened muscles or trying to increase range of motion. Do all poses but do not try to stretch the shoulder. When you feel the shoulder stretching, back off. Best is Vinyasa form of motions, go into and out of pose – inhale in, exhale out repeatedly. Do not try to hold the poses especially if you feel the effect in the shoulder whether it is a stretch or a feeling of strengthening. Either way can irritate problem.