Iphone 6s plus 128gb DISPLAY ISSUE

Good morning, in the last 4 months since i bought my iphone , i have been experiencing some big display issue. when scrolling through facebook app, suddenly this vertical red lines appear on my display for a few seconds and after that dissapears , anyone has any explanation?? At the begining i didn't pay so much attention but after all this time i start to get worries. I request that the apple expert give some answers, as a costumer i have the right to request for help , especially for paying a bunch of money for this phone. Is it a software issue ? or hardware? Down bellow you have a sample of the issue . PLEASE HELP