MSG in beer! Among other things...

I get headaches from MSG aka Monosodium Glutamate. I consider myself a MSG detector at this point in my life.
I recently detected MSG in Miller 64 beer.
I can drink 4 Guiness in 2 hours and get absolutely no headache.
One Miller 64 or Miller light and I have a pounding killer headache for 24 hours!
So after several attempts at this (and thinking it was something I ate, not the light beer) I Googled "Miller 64 MSG" and there you go! It has MSG in it.
Yeungling regular, no MSG. Yeungling Light, yes it has it.

Here are a few other things that have MSG that you may not consider.

Most of these are from my own experience, or combination of that and I read it on the ingredients after I got the headache.
Doritos. If I eat just 3 of these chips I get a headache for days.
Most sausages, like Italian or Bratwurst. Johnsonville is packed with MSG.
Campbells soup, especially cream of mushroom. Even the ones that say no MSG added, yeah, it has it. Cream of mushroom soup is the main ingredient in "Green bean cassarole" at thanksgiving. Stay away from that.
Movie popcorn butter. Usually just the popcorn is fine, just don't add the chemical laced butter.
Most frozen dinners.
Taco bell. Especially the nacho cheese, and hot sauces in the packets. The ground beef has a small amount. Good to go at Moe's and Chipotle. Tijuana Flats I have gotten a headache from once, but could have been the hot sauce I put on it.
Chinese take-out, duh. If you ask them to not use MSG, keep in mind usually it is in the soup because that is made in a batch, and the egg rolls also. Otherwise they can skip it when they make your food.

Also, I can tell you MSG allergy/headache is inherited. My dad has it (mom does not), I have it (wife does not), my daughter has it. My brother does not have it.

Hope that helps you if you get a headache after one light beer!