Galaxy S6 Edge :: Touch Screen Unresponsive - Horizontal Blue Line Moves Up And Down

A couple of times now I've had this problem where I go to use my phone or read a new text that has come through and when I go to enter my 4 digit pin the screen is not responding & I have this blue horizontal line that moves down from the top of the screen continuously like its doing some sort of scan over the phone. I have no way to stop this or to have the ability to enter my 4 digit pin for accessing my phone.

Eventually I give up trying to enter my pin & put my phone down for hours. When I come back to try again twice now I've been able to use my phone like normal and the issue seems to have gone away but other times this still remains for a longer time then randomly starts to work as normal. I've forced my phone to turn off & or reboot but this still isn't fixing the problem. I haven't been able to access my phone for over 10 hours and I have miss calls & messages that people have sent me but unable to get past my 4 digit pin to read them.