Article 'a' with the word pain: "I have a pain in my body"

[Aarora13]

I have a pain in my body.

here article 'a' is used with pain.

I was thinking that we can place article 'a' with only singular countable noun.

is pain countable noun?

please help.

[Jamie (K)]

If pain is specific very localized, it's sometimes possible to use the article "a" with it. If it's generalized pain, we wouldn't use that article. So, you could say, "I have a pain in my knee," if it is one specific pain in that one place, but you'd have to say, "I have pain all over my body," because that pain is not confined to one small place.