I am 62 yo male who exercises vigorously everyday. I have noticed recently that I have a very dull pain or just pressure in the back of my hands and to a lesser extent the tops of my feet. Since all my vigorous exercise is playing singles tennis, which I have been playing at a very high level my whole life, and I am a one handed, right handed tennis player I can't blame the pain / pressure in the back of my left hand on all my exercise. This pain / pressure is more noticeable when I open my hands wide or extend my feet. I do not have any point tenderness or joint pain. I feel it is in the tendons that run in these areas. Any thoughts as to a differential diagnosis?