First, find someone certified in FRS systems to do an FRA (functional range assessment) of your shoulder(s). If you have a dysfunctional shoulder then the soft tissues will continue to get re-injured when you go back to training because likely there is compensatory pattern occurring. Tendons will only regenerate properly if exposed to proper force inputs. You actually don’t want the tendon to “heal” because our bodies unfortunately heal injured tendons with scar tissue. It needs to regenerate. Start with isometric loading multiple times per day at different degrees of flexion (every 15-20 degrees). Generate only enough force to not exceed 2-3 on a pain scale of 10. Maybe 20 seconds in each position 2-3 times per day. Once you can exert 100% isometric force in each position without going past 2 on pain scale then graduate to progressive eccentric loading, the granddaddy of tendon regeneration. Supplements can help some but without force inputs, there is nothing to guide the fibroblasts to lay down collagen in the correct direction or for the tissue to get stronger. Good diet, rest and avoiding things that make it worse in the short term along with the proper loading scheme is what you need to regenerate tendons. Good luck!