How long have you had these headaches and how severe are they? It could be caused by many different things, food, caffeine, sleep deprivation, lack of water/liquid intake, a cold, it could be your braces too even. I've even gotten headaches from watching tv too much and/or being on the computer for too many hours a few years ago. It's probably not a big deal but you should probably just go to the doctors and they will be able to pinpoint it for you. It's not entirely uncommon for headaches to last for days, I know a few people that had that situation before. Worrying about it will probably make it persistent as well, since sometimes when someone gets worried/stressed they develop a headache. Mind you, I'm no doctor but those are just a few of the things that could be happening. If it increases in severity and duration then I suggest seeing a doctor just to be safe.
