I asked a similar question on another Q&A website and got different answers from native speakers. Some of them even said I shouldn't use "a" before toothache and backache, but some said I should. It seems to be a regional variation.
The question is do we make headache, toothache, etc plural in accordance with the subject or do we use the singular form at all times? Consider the following examples:
"The children have a toothache / a headache / a backache / an earache / a running nose"
"The children have toothaches / headaches / backaches / earaches / running noses"
Which one is grammatically correct?
P.S. In my example sentence, when we say people go to the dentist, are we talking about dentists in general or are we talking about a specific dentist?