Our almost 4 yr old is complaining her one ear bothers her after a bath or the pool. Should we take her to see the dr?

Swimmer's ear. If your child is constantly complaining of pain in one or both ears afer swimming or getting water in them, she may be suffering from swimmers ear or otitis externa. This is a common infection during the summer months and needs to be looked at to get proper treatment. If she has pain when she lies on that ear or when she is chewing, or even if you touch the ear, it is a sign of otitis externa.
Otitis Externa. Could be the beginnings of an external ear infection (swimmers ear). They sell swimmers ear drops over the counter, but they are mostly to prevent swimmers ear. I would have her checked out, the doctor will likely give antibiotic drops if it is swimmers ear.