Screen red line problem

@moosakhan without seeing it and only going by your escription, this sounds like a failed screen. Replace the display and while you work on it check the display connector for any bend or broken pins.

Since iFixit does not yet have a specific guide for this, use something like this video Replacement screens are readily available at many online stores.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same issues with their phone. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!