Some years ago I played tennis 2-4 times a week and competed in local tournaments on weekends. As a consequence of many hours practicing the serve I developed a very sore shoulder that plagued me for about a year. On a visit to a chiropractor for a sore lower back, I mentioned to him about the sore shoulder. This guy was also a body builder with, I assume, an extraordinary interest in anatomy. He gave me a series of two exercised and to my amazement, the soreness was gone in a few days and never came while continuing to play and compete. My suggestion is to find health care people who are also athletes. Maybe even find the tennis pro at several local clubs and ask if they can recommend someone a physiotherapist .