You might have some liquid/water damage.
If you take it to the apple store they will flashlight in the bottom to see if there's a red dot if so it's water damage and they will try to charge you 200$ for refurb..
Be nice and try to swindle your way to get a replacement for free.
My friend did this yesterday when it decided to just turn off then be WHITE screen of death.. he said there was no water damage and it was 1 day after his warranty ended..but they gave him a replacement for free ...what a coincidence
goodluck.
