The touchscreen issue was happening in my phone after playing Nova 3 for a while. After some days I found out that, just wiping the screen with a clean cloth solves the problem. I used to pause the game, just a single wipe on the screen with a cloth will do it just fine.

Sony W700i-->Sony K810-->Sony K220i-->Samsung Galaxy 3 i5801-->Samsung Galaxy Note GT-N7000--> Xperia Z1 C6902 + Sony MN2 Smart Watch.