why do some commercial beers give me headaches?

I could never figure out why some commercial beers....especially coors, bud, miller....will give me a nasty headache after about 2...sometimes even just 1. When i drink my homebrew i never get them..ever...just a nice clean buzz and i wake up feeling great. Anyone else have the same problem? I mean not that's its much of a problem as o don't care for cheap beer. I'm wondering if the sugar used to ferment cheaper light beers has something to do with this.

Corona is an instant headache! Is maybe some of the finishing agents? Cheap sugars? Or just because its just crap suds?