Welcome to the Healing Well Wrapped Club! Glad to hear your surgery went well and your home and healing. I agree with your doctor that your shoulder pain can be helped by walking. Just do as much as you can tolerate.
Short walks often, can work well. When I was in the hospital, the night nurse suggested walking the hospital halls whenever I got up to go to the bathroom. It was good advice. I always found that the more I walked, the less my shoulder hurt.
Again, glad you're on the other side!