Generally, books that are divided into chapters were split up that way because the author wanted to be able to change the focus from one cluster of characters or one course of events or one setting to another cluster of characters or another course of events or another setting. Imagine attempting to read a Dickens novel that wasn't broken up into separate chapters or Tolkien or something like that. It would be completely impossible to retain any sense of flow without them. But if you're working on a short story, anything less than say 15,000 to 20,000 words, you really don't need to divide your story. Authors use chapters so that things that ought to be separated from other things can stand on their own. And the books are not usually written chapter by chapter. The chapter breaks are often decided after the entire book has been completed. Though not completely unheard of, a 3 page chapter would seem like a bizarre stylistic choice and most readers would wonder why the author bothered.