i had the same problem with my phone.My screen was unresponsive at times and i could find ghost clicks when i kept holding the same spot while using instagram or fb.I noticed the problem from today morning.I do repairs on my own and tried my best but couldnt figure it out this time.Then i thought about the exact time this happened.It was from the moment i started using a fake iphone/ipad charger which i bought from ebay.That might have messed up with the circuit inside.Also i guess removing the case also helped me.Also if you have a dry screen,you could apply a little bit of vasiline on a microfibre cloth and rub the screen gently with that.And for those guys who said that they got horizontal stripes on the screen,its definitely a problem with the flex cable.Re-installing it may fix the issue.Or try cleaing the flex cable with a brush lightly if it has signs of corrosion(if it was ever water damaged).Hope this helps.