Chosen Solution
The black vertical lines only appear on the right side of my iPhone screen. They appeared after I dropped my phone on cement. No cracks are visible and, I have a case but no screen cover.
A screen is composed out of different components. On the inside you have the LCD which displays the actual images, in the middle you have the ‘digitizer’ which responds when you touch the screen, on top you have the protective glass. When discoloration or vertical / horizontal lines occur, the LCD is most likely cracked or damaged by the fall; even though no cracks might be visible. You should try to replace your screen, it’s fairly easy and iFixit has a guide: iPhone 5s LCD and Digitizer Replacement
Junk it and buy A Sonim XP7.
