By: Addison Wylie Many associate angst with Kurt Cobain.  The feeling is riddled throughout his musical work and how he presented Nirvana to the world.  With Kurt Cobain: Montage of Heck, documentarian Brett Morgen (The Kid Stays in the Picture) has peeled back the musician’s enigmatic career to find the origin behind his hurt and disassociation. Cobain is respectfully represented as someone who was robbed out of an upbringing he wished he had growing up…