Could be an inquisitor, interrogator, questioner, or just curious.
Another option is "querent."
He would be called questioner / asker.
"inquiring" minds would like to know...the "questioner" has a inquisitive mind....or let's call them blurt it "inquirers",explorers,knowledge seekers...
The asker. And the person who answers is called the answerer. I think.
That would be the asker, like you asking the question, and I am the one who answers, and that makes me the answerer. Hope this helps.