Pain in lower back / left hip area after every session!


I thought a long time that our mattress is the reason for my back pain and not tennis. So in summer I was sleeping often on other mattesses and the pain was still there.
1,5 months ago I changed the side of where I am lying on the mattress with my wife, and my pain got less. I have to say that I also play less than before, and I also changed shoes when playing! So a lot of factors which come in play, and I cannot really say what it is, just that atm I am much better. Unfortunately my ellbow got worse, which I have to do an MRT xray next days..