Ghost touch before and after screen replacment

So i had this phone and its about 1 year old,althought by the phone being new it screen had ghost touch ,after few months it got damaged and it was left on shelf for like other 5 months. I just got a new screen on it and i still have ghost touch. Before repair it had ghost touch on top right corner now its on the bottom in the middle. i still have 6 month warranty. Now my question is could this be a mobo issue? It was dropped previously multiple times, but ghost touch is now in different area so could problem be a new screen??? Is it worth going to repair shop again? Thanks in advance:)