Iphone 5S screen randomly stops responding.
Basically my problem is that the entire screen will randomly either stop working, or occasionally I get an issue where the inputs are revered; i.e I swipe down and it's as if I swiped up. If I lock and then unlock the screen the issue is fixed for anywhere between 5 and 30 seconds and then it will just stop responding again, I've tried to both restart and restore the phone and neither has had any positive effects on the issue. I haven't dropped the phone or noticed anything else that could have damaged or caused such an issue, maybe exposure to heat as it's quite hot here in my town right now, but apart from that I'm completely dumbstruck as to what's happened and if it's possible to fix myself.
iPhone 5s, iOS 9.2.1