Flickering screen. Broken lcd, software problem or loose cables?

So I had the screen repaired a month ago and I dropped it on its power button side about 6 inch height. The screen started flickering showing after images for about 10 seconds and then everything returns to normal like no flickering at all. Everything is fine including the touch and pixels except for the annoying flicker. Not sure if this is relevant but when I plugged it in and tried to copy the photos in the pc, whenever it flickers, error occured. It also flickers during a restart the one with the apple logo.