If you realize that the major contributing factor with your back pain is gaming, stop gaming for a while and begin to do some simple streching excersises. Look for some info about streching at Spineuniverse.Com and also look for a more ergonomical chair to sit in while gaming.
I have not played games since I was about 22, right when I was getting out of the navy, I used to have a nintendo and super nintendo, if that gives you any idea how long ago it was. I am now 33 and still I do not play.
You really need to look after your health because as time moves on, back pain can only get worse and when you think you have reached the max amount of pain, you will find that there is more in store.
Take care of yourself,
brian