Many things can cause a sore tongue. Generally if you have braces or dental work, or even a chipped tooth, the tongue’s first reaction is to toy with it. Any time something new is in your mouth, your tongue fidgets with it like it’s going out of style. Secondly, rough, abrasive, or acidic foods can also cause a sore tongue. I eat pretzels, big bags of them all the time. And my tongue is usually so raw i want to weep.