Sudden hives?!?

Today at the movie theaters my neck started itching. I thought it was nothing but throughout the movie my whole body was itching. Then outside I saw my arms had big red bumps on them. My friend said maybe its somethin' I ate. But I only ate McDonalds and popcorn. And I always eat that so it doesnt make sense I would have hives now. Could it be the chairs? I read online that widespread hives could be a sign of a viral infection? Should I go to the doctor?