The xbox 360 controller hook up is not working correctly the looking up down left right buttons are set to the triggers

Looking up and down buttons are set to the left trigger press to look down let go to look ip. Left and right is set to the right trigger press to look right and let go to look left.... Why is it set that way you don't even provide the option to change it..... Could you please fix that? It's been like that since the game was released.