"My profession is hard work."
Translation:Yrket mitt er hardt arbeid.
I think Jobb would be used about the same as in English. So you could say ''Jobben min er hardt arbeid'', but the other way around would be strange.
Arbeid (english: work, labour)= the things you're doing, either to earn money or to finish the chores around the house, etcetera.
Jobb (english: job)= a regular activity performed in exchange for money.