You have an iphone 6 plus like me and I had the same problem. I read a lot for this problem and I came to the conclusion that this is a problem with the touch sensors on your iPhone and must be replaced. This is a bit difficult but no matter see this video and i suggest you to try it...https://youtu.be/iKb2itJlxZ0

When your phone fell and the screen cracked, perhaps touch sensors on motherboard of your nexus is crashed too. So maybe, is the problem with touch sensors and not the screen. Check any videos in iFixit how to replace it.

Robert, this could be caused by a failing inverter, bad ccfl as well as bad capacitors on the main board. I would suggest to take a look at the mainboard and check the capacitors for any bulging, leaking etc. Remember that there was a big issues with Samsung having used sub par capacitors. Your TV is part of the group that was affected by this. Check this site.. Of course it is also possible that this is a bad white balance. Go into service mode and see what checksum you get on White balance. It should be 0x000. to access the service mode Turn the power off and set to stand-by mode Press the remote buttons in this order; POWER OFF-MUTE-1-8-2-POWER ON to turn the set on. The set turns on and enters service mode. This may take approximately 20 seconds. Press the Power button to exit and store data in memory. - If you fail to enter service mode, repeat steps 1 and 2 above. There is also a way of resetting your set to factory default, I'll keep you posted. Hope this helps, good luck. Update To access it would...

This isn't a problem with screen of iphone but with touch sensors that is on motherboard. Check for any videos in iFixit how to replace touch sensors of iphone that you have.