I have sores all over the inside of my mouth....what could it be?

Are they just canker sores? When i eat food like crackers, i can feel it rubbing against parts of my mouth and it starts to hurt. It feels like i have a sore in the very back of my mouth, two on my tongue - one on the tip and a sore spot on the back.....tingly on the roof of my mouth. What could it be? They're all on the inside and i haven't been sick lately or anything....