What is the term when someone asks the same question over and over because he is trolling.
Spamming might work, but I would like a more formal word.
I got mad because he was ...
which means to annoy or irritate somebody with constant urging.
It is often used to indicate constant complaining, but it works here.
harass, badger, give someone a hard time, hound, harry, criticize, carp, find fault with, keep on at, grumble at, go on at;
I got mad because he was nagging/badgering/harrassing me.
To behave in an annoying manner towards someone by doing or asking for something repeatedly.
John has been pestering her to go out with him all month. (Cambridge Dictionary)