Black Horizonal Line on Macbook Pro Screen

Today when I opened my Macbook, I saw a horizontal line on the right side of the screen, and the line gets bigger when the screen seems to rest on its axis (when I push the screen down to move it the line expands). However, when I relieve this pressure (pulling the screen up in the motion that closes it), the line vanishes. Could this be a problem with a connector to the screen or does the screen need to be replaced? I need my mac for school and have apple care + but it looks like their lead times are long so if I were to take it to a local non-apple repair shop would that void my apple care+ warranty? Thanks in advance!