I used to get em like a muthafucka, for no reason. but alot of the times they were triggered by heat... like when it's hella hott out n shit. I broke my nose a few times so that caused me to have a deviated septum but i finally got surgery dun and i haven't had a nose bleed since.
You ever broken your nose? maybe that's what you have too...
I like how when you pinch your nose when your nose bleeds and that BIG ASS BLOODCLOT forms in your nostrils. Then you can either blow it out, or hork it up and spit it as a bloody ass loogi.