I'm fairly new to tennis (few months now) and been playing quite a bit in the past couple of weeks. Lately i've noticed that during and after games (and sometimes hours after) i have a lot of pain in the muscle tissue between my index finger and thumb of my hitting hand. Doe anyone know why this is happening? will it go away? am i doing anything wrong? also.... my knees have been going thorough rough times and sometimes its hard to sit up/down.