L.H.
My daughter, now four years old, was born with enlarged tonsils (they are huge and coming out next week - woo hoo!). Sometimes when her tonsils are inflamed (she does not necessarily have a sore throat when this happens), she will chew up her food and spit it out. She does this because sometimes it is just too hard to swallow with the tonsils so big and she gags. She has had tonsillits some and has no problem letting me know her throat hurts, but usually, when she is spitting out her food, it is not during a bout of tonsillitis - her tonsils are simply larger than their normal huge state thereby leaving little room for the food to squeeze through.
If this is not the case, I would still second the recommendation of speaking to the doctor. He may be able to say just the right thing to stop it. I have "used" our family doctor for just such things.
Good luck.