So i have played tennis on and off for about 10 years but only this last couple of years started taking it more seriously- entering tournaments, playing almost every day etc. I am an athletic 23 year old and have always been pretty healthy but this last few months i feel like im 50 something!! My back aches every morning, my elbow hurts for the first 10 minutes of hitting, ive had pain in my shoulder, ive recently pulled my groin so cant play at all now! why is this happening? What do you guys do to prevent aches/ injuries?