Cold teeth

My eldest son has no cavities and is relatively healthy.

They complain that their teeth feel cold when eating only fruit, that chewing feels uncomfortable, or that their teeth are bothering them.

Every time we go for a dental check-up and ask, they say that the alignment is slightly irregular and that it might cause the gums to be pulled up, and they have taken measures, but there has been no significant improvement. There are people with more irregular teeth than our child who eat fruit without any issues, so why is it only our child experiencing this? Maybe because our child is a bit sensitive... It gets worse when eating sour grapes, and they also dislike apples. Are there others like our child?