(uncountable); job is mostly used as a noun (countable).
To
work - to do a job, especially the job you do to earn money.
Examples:
I’m busy – I have a lot of work.
I have two jobs – I’m a taxi driver, but I also work as a part-time fireman.
All jobs involve work but doing work isn’t always part of a job.
Someone can spend the weekend working in their garden. However, this is a free time activity, and so it is not his or her job.