Lots of research tying migraines to consumption of MSG in its various hidden forms.

Check out these pages:

11 Natural Remedies To Relieve Headaches (Drug-Free!)
Dump toxic pharmaceuticals and use lavender essential oil for migraine headache relief instead
Ginger may protect the brain from MSG toxicity, says fascinating research
Coping With MSG: Names and addresses of ingredients that contain processed free glutamic acid (MSG)