My 5 year olds teeth...?

my daughter went to the dentist with complaints of her front two top teeth hurting. The dentist told me they were starting to loosen up that is why they are bothering her. That was a little over a month ago. Now I havent noticed them becoming more wiggly and she is now complaining of her bottom two teeth hurting. Is this normal? She is only 5 how long will these keep bothering her?