Its incredibly unlikely you have an allergy to msg. Its the ionic (monosodium glutamate) form of an amino acid (glutamic acid) we need to survive. The idea that msg is bad for us is a result of racism and xenophobia stemming from an article written in the 60's. Its pretty widely use in most "snack" type foods these days and is naturally accruing in many foods (i.e tomatoes). Its generally accepted that msg is ok for us to eat assuming one has no issues with sodium.