How do I solve my screen buttons problem?

[Exorcisto]

So I have a Sony Xperia Z3 Compact phone and everything was working fine until some days ago. My back and home on screen buttons stopped working but the multitask one still works. The problem is that I do not think the screen is the problem because if I lock my phone I can unlock it from that area where those buttons are placed. If I rotate the screen so the buttons are on the opposite side they work. I really do not know what to do.

[VJIADIS]

Turn on the phone, connect a mouse to it, via usb, give a minute maximum for detection, If it works then the problem is with digitiser. You will have to replace the screen plus digitiser combination. If mouse is not working, it's some issue on main board.