hi all.

I have some dumb questions and I need help.

In american greeting or conversation, when people say, "what's going on", or "how is it going"?
do they mean to say HELLO or do they mean to checkup and expect a verbal report of what the listener is doing? I do not understand, what's going on, in my native language, sounds like an interview question and therefore, it evokes uncomfortable and unwelcome feelings. It is not a good way to greet people. Someone, please verify what the Americans really mean when they say what's going on, how is it going, what's the dilly.

My second question, do i use singular or plural noun after any or every.
ie1) Kathy does not have any pen.
ie2) Kathy does not have any pens.
First question.

My normal response to "What's going on?" is "Sorry, I haven't a clue what you're talking about. Could you be more specific please?". I guess it means "What's happening?", so without context it's a useless question.

"How's it going?" is just a greeting. My normal response would be "Fine. And you?".

Second question.

In this context, you need "any pens".

If this were being written rather than spoken, wouldn't
Kathy has no pens
be preferable?