Why is my chromebook screen glitching out

I don't remember when this happened, but whenever i tilt the screen, it glitches out, and the only way to get this thing to work, is to close and open it over and over again, sometimes I really lose my temper on this thing and just close it and open it agressively, yes I tried turning it off and on, so if anyone can tell me how to get this back working willy nilly, that would be great, Thank you.