I get these painful mouth sores that hurt when food rubs against them. what could be causing them?

See a doctor: There are many causes so have a doctor r check you out...

Mouth sores: The list of possible causes of mouth sores cannot even fit within the space allowed us for an answer. Even if we gave you a list of possibilities, you wouldn't know which type you had, why you have them and what to do about it. Therefore, it would be wise to see a local dentist for an accurate diagnosis, along with appropriate treatment if necessary or advice on prevention, if possible.