What Peachey has said is right but I will break it down a bit more and give a few examples for you. First of all, "to work" can be used as a verb, whereas job can not. "I am going to work right now." "Where is it that you work?" Those are both correct because "to work" is a verb. ----- When used as singular nouns they are very similar. "What work do you have?" = What work are you currently engaged in? "What job do you have?" = What is your current occupation. It's a little different because "work" is a little more general and could include more (studying for instance). "Are you working right now?" = If you said this to a student then you might be asking if they were doing homework, for instance. ---- "Jobs" can be used in the plural in the above senses. "How many jobs have you had?" = How many different jobs have you had?! You CAN NOT use works in the plural this way. --- Finally, you can use "works" in the plural (as a noun) but it takes a different meaning. It usually refers to pieces of art, novels etc. that are the result of someone's "work". "How many works of art did Van Gogh paint?" ---- Hope this helps :)!

Actually, the difference is very simple. Work is uncountable; job is countable.

Your job is the work that you do regularly in order to earn money, especially when you work for a company or public organization • My last job was with a computer firm. • He finally got a job in a supermarket. Work is used in a more general way to talk about activities that you do to earn money, either working for a company or for yourself • Will you go back to work when you've had the baby? • I started work when I was 18. !! Do not say 'what is your job?' or 'what is your work?'. Say what do you do? or what do you do for a living? (http://www.ldoceonline.com/dictionary/job)

shift work jobs