It does sound like a tooth-problem, most likely with the inner teeth. It’s not uncommon in bunnies. Since their teeth grow all their lives, their teeth needs to be constantly worn down. This is primarily done by chewing tough plant-matter (hay, grass). If the jaws are slightly misaligned, this won’t be effective enough, and the teeth will grow spurs. The spurs can hurt the tongue or the cheeks, and the bunny becomes reluctant to eat, esp tough food. This in turn means the spurs don’t get worn down but keep growing.
A vet can see a buns inner teeth with an otoscope, but if the spurs are small or the bunny feisty, the bun might have to be anesthetized for the vet to get a good look. The spurs can then be ground down with a dremel-like instrument.
I have a bunny who needs his spurs ground down from time to time. Many of us here actually do, because it is rather common. Many buns don’t get the proper diagnosis the first time at the vet, because even really, really small spurs can hurt a bunny. But what you’re describing is typical: The bun wants to eat, hops over to get food and tries to eat, but drops the food or eat it in a weird way while looking pretty miserable.
My bun needs a pain-killer after a dental, so you should ask for that. There’s no sensation in the molar spurs themselves, but there can be soreness in the gums.