I also suspect that MSG is migraine trigger for me. I have been noticing headaches cause by other migraine trigger foods. I realized after having sauce with MSG immediately caused headache but another sauce without MSG and same dish didn't do anything.

MSG as migraine trigger fits a lot of the old reporting of MSG intolerance. I wonder if science didn't know about food triggers food triggers, and there was less recognition of migraines. It is interesting that there hasn't been studies finding MSG as migraine trigger. I have seen studies that didn't find headaches in general but I wonder if focusing on migraines sufferers would show something different.