When I eat pineapple my tongue burns for 2 days n sometimes I get sores in my mouth could I be allergic or is this normal?

Acidic foods. Pineapple is a very acidic and rough food to eat. It is very common for this to bother your tongue after eating it. It happens to me. I doubt your response is an allergy. Lay off citrus for a few days and things should improve. Also avoid extremely hot, spicy or acidic foods while this is healing. .