Is the MSG in Chinese likely to give you a headache?

Short answer: No

A review of 40 years of clinical trials, published in thejournal of the American Academy of Nurse Practitioners in 2006, found that all previous research "failed to identify a consistent relationship between the consumption of MSG and the constellation of symptoms that comprise the syndrome," including headaches and asthma attacks.

The misconception spawned from several poorly-done small studies in the 1960s that seemed to connect MSG with a variety of maladies that people experienced after eating at Chinese restaurants.

Well this is god because I do like my Chinese food.