Have you asked the person to stop? They might not understand what they are doing is bothering you.

No one can offer a classification based on one person's description of the interaction. You should ask a trusted colleague who witnessed the behaviour.

Your coworkeright be insecure and hypersensitive about your opinion of them or they may be misinterpreting your focused face for angry.

The real key is a few more examples of questions he asks you, from that we can determine if he's an idiot, if he's messing with you, if he's being disrespectful, or if he's being shady, or even if he just likes and respects you, and is struggling to win your approval.

So a little more context will help us help you, and to be fair, you will probably realize the answer for yourself by doing this.

Have you tried telling him "sorry, but I'm busy right now"? Or simply "hey, I don't like distractions while I'm working"...

Answer with a short curt "ok" and don't engage. Make it clear you don't like it first before going to HR or making a scene.

Also, make sure he isn't doing this with everyone. Some peeps are a bit weird and you'll come off as a dick if you make a big deal out of something which, in the end, is just a minor annoyance.

Inb4 he's flirting but autistic so doesn't know how to do it without coming off as agressive /j

Less jokey tone, if he's making you uncomfortable, have a word with him about it and say he needs to take a second to think about the way he's saying these things, because they're making you feel bad.

If he continues after youve spoken to him, then it's time to talk to your manager.

If the manager is worth their salt then they'll speak to him without making it an HR problem, but there will be a record of it happening in case it's malicious and he doesn't stop, which will definitely require HR involvement

"I'm fine; if it's ok with you I'd rather not have these kinds of conversations".

What do you say when he says you look angry? its a pretty normal thing to check in with someone when thry look visually frustrated or upset.

Just say "haha nah, I'm fine, I didn't think I was making any face in particular, maybe I'm making a face subconsciously because deep down I'd rather be doing something else." Then as other posters have said, if he continues tell him you don't appreciate his constant commenting on the topic and would like him to stop. If he continues from there then tell HR he's harassing you.

Kinda sounds like flirting. Have you let them know you're not interested?

Do you mean mogging? If so, no this is not mogging, but also worth bringing up to HR if it is continuously bothering you

talk to your supervisor/manager about this and ask for their help

going to HR might be jumping a little ahead too fast

Send an email to your supervisor so it is in writing. Any time this person does it, send an update email. If that goes nowhere, email HR. Make sure you indicate the exact date/time/location, exactly what was said, why it makes you uncomfortable, and who else could have witnessed it. Paper trail with all of this information is extremely important.