headaches

what causes a headache? is it simply just chemicals colliding in the wrong way and making you miserable? if that is the case why is it they always seem to occur at the most in opportune times. over the past week, i have had 4 POUNDING headaches. so bad, im pretty sure the people next door heard them. are they stress related? are they anger related? i can't see why being happy would cause a headache, otherwise im pretty sure people would be walking around with them most of the time. whatever causes them, the out come is always the same: pain, unpleasantness, and - i say this without shame - grumpiness. i guess on the bright side, you can at least count on them to always be that way. at least one thing in this world is consistent.