Maybe you should read my post #78
Registered Dietician/Licensed Dietician on the Mayo clinic website states there are apparent reactions to MSG reported by some people. It is known as MSG symptom complex.
Although researchers have found no definitive evidence of a link between MSG and these symptoms (one of which is Headaches), researchers acknowledge, though, that a small percentage of people may have short-term reactions to MSG. I do not have a reaction to MSG so I do not comment but your definitive statement that "MSG has nothing to do with headaches" is yet 'unproven', one way or the other, according to the Mayo clinic and scientists who do research in that area.
It used to be only death and taxes were inevitable. Now, of course, there's shipping and handling, too.