Screen keeps dimming of doesnt work at all when dropped

I recently opened my iphone to fix the off on button but i could not do it so i then closed my iphone. Ever since then every time i put my iphone down a little hard or the iphone falls about three inches, the screen dims to a super low brightness or it just goes completely blank. At this point i have to connect the iphone to the computer and restore it and it works again. Can someone tell me why this happens? Can i stop it? I think it may be because of one of the connectors but im not sure everything else works fine (with the exception of the off/on button which has been broken for a while now).