Cluster headaches aren't really "headaches", I'm pretty sure it's a problem with nerves that are in the head. I remember reading somewhere that the pain with cluster headaches is usually located directly behind the eyeballs, and people describe it as "not even hot pokers gouging out eyeballs seems as bad".
On a curious side note however....I used to suffer from migraines. I started getting them when I was 14. I would always get an aura consisting of bright rainbowing globs of flashing light (not as fun as it sounds, trust me). I am 24 now, and I have been using psychedelic drugs for the last 4 years, and during those last 4 years, I no longer get migraines, just aura without migraine.
For those of you who don't know what this is:
http://en.wikipedia.org/wiki/Migraine#Aura
But yeah, I have ingested large quanities of mushrooms, LSD, 4-aco-dmt, and other serotogenic psychedelics, and unbeknownst to me if they are in any way related or not, I do not get migraine headaches anymore, just aura without migraine. Still pretty annoying, but hey, i'll take it !
I used to take sumatriptan when I was 14-15-16, but yeah...seems like after I turned 21 and got into "the good stuff" the nature of my headaches really changed a lot.