Has the phone been dropped? Maybe the connection from the ribbon to the board isn't seated properly? If you're ok with opening the phone up, maybe check it isn't loose?
Alternatively, if it's a bad screen, then you'll need to replace it.
Nope, not dropped it recently. I think it's probably the screen that's faulty. May crack it open to check the cable. When scrolling it has started to ghost pretty badly on occasion. Really annoying, I hate phone shopping. May look at changing the screen.
