Business – plural form or singular form

The word business has several different meanings. One is “commercial or mercantile activity engaged in as a means of livelihood”. So Microsoft is a business, Air India and Aeroflot are businesses, and so forth. In this meaning, business is countable, and we have to use an article or counter with it.

Another meaning of business is “an immediate task or objective”. In this sense, business is usually not countable, so you do not pluralize it or use an article or counter. “I have important business to do”, but not “I have important businesses to do” or “I have several important businesses to do”.

Saying “I had some businesses” would mean that you had several different companies. But “urgent” doesn’t really make sense in this context (how is a company urgent?) so the sentence is wrong.

We don’t use some with singular nouns, but we do use it with uncountable nouns, so you can have “some business”, just like you can have “some sand”.