Lyric discussion by GregYan 

Cover art for Tear in My Heart lyrics by Twenty One Pilots

I believe this song is about a girlfriend he used to have friend when they broke up she left a tore in his heart that cant be fixed. Or one completely different approach is that she is the only he's met that is able to penetrate his armored heart and make him feel love.

@GregYan Sorry, incorrect grammar, here is it corrected:

I believe this song is about a girlfriend he used to have and when they broke up she left a tore in his heart that cant be fixed. Or one completely different approach is that she is the only he's met that is able to penetrate his armored heart and make him feel love.