「仕事は何をしていますか」"What is your job?" or "What do you do for a living?"
「今、何をしていますか」"What are you doing?" ("now" is not needed, it's implied in context)
「今、朝食 を 食 べているところです」"Incidentally/By the way, I am eating breakfast right now."
「本を読んでいます」Needs a subject in English. "I am reading a book." or "She/He is reading a book."