For many stories I have seen, written or otherwise, a fight or some intimate moment is used to hook the reader. It is done A LOT, if not every time. Does a hook have to be in the beginning? Are hooks even needed?
Hooks can be:
All these can signify to the reader that the story or book is worth reading.
A new Stephen King novel will sell no matter its first sentence. I have numerous books (and music records) that I only bought because I loved the cover. I do trust some publishers or editors to select quality books and buy books published in certain series without thinking. If the blurb contains angels, dead children or other things that put me off, I don't buy the book. I did not want to buy Divergent when I read its beginning in the book store, but now that it was made into a movie, I bought it and will read it. And so on.
A hook in the first sentence or paragraph is most necessary for new books by unknown authors. The more quality signals accompany a text, the less gripping can the story beginning be.
You should open your story by creating a question in the reader’s mind that can only be answered by reading onward. Conflict is a popular way to start, because it raises the question “who’s gonna win?”
But the conflict doesn’t have to involve fistfights and explosions. In the first chapter of Pride and Prejudice, the narrative question is “who is going to marry this fantastically wealthy single man who just moved into the neighborhood?” That’s a perfectly effective hook (especially for Austen’s original audience—think of P&P as the Regency-England precursor to The Hunger Games).
And if you do open with a violent conflict, but the reader doesn’t give a damn who wins or loses, it’s a bad hook. And if you open with a good hook, but then switch to twenty pages of boring exposition that has nothing to do with it, you will lose the reader in spite of the hook.
Books of the last, say, 75 years are set in what's called in medias res, in the middle of things. The story starts where the plot starts, more or less.
But back in, for example, Victorian novels, it was much more common to give the entire life story of the protagonist. The really exciting part of Jane Eyre is when she goes to be a governess for Mr. Rochester and all the events which happen as part of that, but the book starts when Jane is a child.
So technically speaking, no, you don't need a "hook" per se, and you don't need to put it in the beginning. But if you don't, your book will feel old-fashioned. That may be a feature rather than a bug, if you're doing it deliberately.