Why do I get back aches when I play racing games?!

Back pains are caused by tight/pinched muscles in your back. The muscles are tight and without pain to start with but as you tense up your body playing the games it causes enough pressure on the muscles to make them go into pain. In time after the pressure is off they will go back to just being tight again but they are not relaxed the way they should be. To make sure the muscles won't do that again you have to free them up so they are fully relaxed and here's how to do that:
Back:
(do from a sitting position)
Place your left hand on your left leg next to your body. Place your right hand over your left shoulder, fingers over the back and the palm in the front and firmly pull down on them and hold. After 30 seconds slowly lower your body forward and to the outside of your left leg, keeping your left arm fairly straight as you do. When you reach your lap remain there for another 10 seconds, release the pressure but rest there for another 30 seconds. Then reverse your hand positions and do your right side.
For best results relax your body first by taking a deep breath and exhaling then remain this relaxed.

Because you sit too long playing games. You need to walk around every ten or fifteen minutes.

LOL racing games are bad luck for you I guess