My teeth second and third from the back have pain in between them?

In between the teeth 2nd and 3rd from the back teeth are sorta painful. It kinda feels like it’s the gum but at the same time if I chew something on that side it’s painful so It might be one of those teeth. Whats wrong with it? If it’s a cavity how will the dentist react to it. I mean what will they do to me? Is this normal? Is it a cavity? Tooth ache? I’m only 13 and O haven’t lost all my teeth. I have 4 more to loose and one of the teeth I’m talking about is a baby tooth and one is a fully grown one.