My iPhone 6 shows grey faint lines and when this occurs the screen freezes

I have tried restarting my iPhone and resting the settings and nothing seems to change what is happening. It is beyond a joke as it happens a lot and is getting to the point of not using the iPhone at all. The grey lines stop me from using the phone and doesn't let me use the touch screen at all the home button and lock button work fine. I have not dropped the phone aggressively hit the front of the screen, It happens a lot and considering this phone is SUPPOSED to be really good I have not seen anything of which that impresses me.

iPhone 6 space grey 16gb.