hey I have your problem solved!! so basically my phone started doing that after a hard smack on the side, which meant that I broke the censor or whatever it was that lets my fingers function on the screen, now the censors or whatever isn't broken, it is disconnected from the phone.
so what you need to do is hold on the right end corner of the phone and hold on the left top corner with your thumbs and hand in a pressure push position, and kind of bend it to both sides until the flickering is gone which means the censor or whatever is connected again inside the phone!!
now if you cant afford a new phone or you're not bothered togo to the store and get a new phone then you can keep doing this, BUT if you drop it again it gets worse, and if you keep bending the phone it will get worse,
the side effects are:
the antenna breaking XD!.
camera damage!!
so the antenna breaks, or malfunctions. so what you have todo is either keep refreshing with airplane mode, OR turn off and on the phone and what I mean is your phone can not reach service, don't worry your SIM cards still works.
now after this starts to happen the phone gets worse, but this is after a year of flickering and bending. or earlier if you keep dropping the phone.
now the phone starts acting by itself and presses buttons you didn't press so when this happens make sure you lock the phone quickly before you call people and you cant end the call because you phone is flickering too much XD
and don't worry about the screen, get panserglass protection on your screen and it will keep it safe by breaking itself instead of the phone.
now after the phone stops getting service and after bending it doesn't work, get a new one, cause the stores cant get your censor or whatever fixed, you will need a new phone XD. oh and btw, your camera is probably really damaged as well and doesn't focus. that reason I think just blends in with the malfunction of the screen. and dont worry when you bend the screen and you hear a sound of cracking, you're just connecting the censor to the screen and that's the sound XD good luck!!
hope it helps.