i have the same problem from past 2 months...its a dead pixel line. the main cause of this problem is that the pixel are not getting enough current or any other name to provide the energy to work...There is an easy temporary fix...Donwload Dead pixel fix app....it will work...n press the upper bezzle on or near front camera....this should work...but show ur device to the service centre for a permanent fix.
After some time that pink tint will spread in full screen slowly...Its a display liquid..my previous mobile was s6..and same thing happened with me. In service center they will change full display nd they will deny to cover that cause in warranty..
I had same problem..it's fault of display but I had to pay for it because I dropped it after a week of buying my phone...and dead pixel line came after 2 months...but since it was cracked I had to pay but if your device is fine..visit service center they will fix it in guarantee...your display will be changed..