Lyric discussion by gsorkin 

Cover art for Haven't You? lyrics by Matt Skiba and the Sekrets

On the surface, it's clearly about loss (death, not a break up). And then you hear it from the horse's mouth in this YouTube video.

"...I wrote this song for my grandmother and it's for anyone here who's lost someone near and dear to 'em." --Matt Skiba

http://youtu.be/W1jmPebQLNE?t=33s

Song Meaning