How do you fix an unresponsive iPhone 6 screen?

About 2 days ago my phone started to freeze worse than usual (freezing for a few minutes) so i just reset it. I reset it several times every time i got on the phone and it seemed to work for a while but then later in the day it just stopped working. Yesterday i was able to get it to work 2 times (but only enough to swipe over to the unlock screen or to touch an app) then it would freeze again. It started to work very well again after school then I decided to turn it off to give it a break ( which was NOT a good idea) so i turned it off for about an hour or so and then turned it back on. Now i can't get the screen to work AT ALL. After turning it off i can't put in the password so now i can't even use my finger print of siri to text like i was before(because it was the only way it would work).

I have been reading online and it says that this has been happening to a lot of people but none of the stuff it suggest to do works (reset phone, turn off phone, clear phone completely. I can't even do the last 2 things because of the fact that the screen DOES NOT WORK.).

How do I get this fixed?

If I take it to AT&T or the Apple Store will they give me a new phone?