Stuck pixel line

[AC Question]

I believe my device has a stuck pixel line. On around the top right of the screen, on some screens of android I see a white pixel line. I mainly see it in lock and home screen. Sometimes it disappears. What I want to know is, is it a physical problem or crack with the display? Or is it just a defect that can be fixed and is not physically damaged inside the display or something? Because like I said, it doesn't happen sometimes.