Why does my throat hurt when i swallow?

Ok so i was with my friends and we had a contest. It was to see how long i can sing against my friend. I never took a choir class in my life but they thought i was very good. She took choir for a long time. We lasted for the whole day... ( we had breaks in between songs) Now everytime i swallow the back of my throat hurts mainly on the left side, jusat a little on the right. She said her throat is fine. What should i do? I dont have allegies and i didnt eat any spicey foods. HELP!!!