Scuba,
I used to play a lot of tennis, until my knee started giving me problems.
Typically if I started observing pain from playing, I would just stop playing for a while, and it would heal up.
Then I got tennis elbow. I rested for over two months. It seemed fine, but as soon as I made contact with the ball hitting a backhand, I would get a very sharp pain down my arm. So resting didn't seem to help. I even tried to change over to a two handed backhand, but I wasn't very good at this.
I finally went to a physical therapist. They gave me exercises with a large rubber band. I would sit in a chair with my forearm laying on the top of my bent leg. The rubber band wrapped around the back of my hand, and down around my foot. I would lift my hand up and down against the resistance of the rubber band. I would do three sets of 100 lift/lower cycles, and then turn my hand 180 degrees (palm up), and repeat doing three sets of 100. It hurt like crazy at first.
Within a week of doing these exercises, the pain was gone while playing tennis, and my arm was stronger than ever.
I am now a big believer in physical therapy.
Good luck,
JP