QUESTION: Do I really need real world experiences to write fiction? In other words, can I write a fight scene if I’ve never hit anyone or been hit?
Real life experiences can certainly inform your fiction and give it realism, but I don’t think it is absolutely necessary.
I have written space battles without being an astronaut, diving scenes and I can't swim, and fight scenes using swords, fists, and futuristic weapons, and I have never used any of them. (I am a pretty good shot, though.)
I've never had the first reader tell me that I got any of my fight or action scenes wrong.
I have never been punched, but I used to ride. I have had a horse smash her head into me. I've been kicked, knocked into a tree, and have had a six-hundred pound horse fall on me and step on me when she was getting up.
All that has given me more than enough visceral information about taking physical abuse to use in my writing.
I got my diving scene right through research, then I ran the scene past friends who do dive to check for accuracy.
However, the more you write about something in particular, say your main character is a diver who spends much of the novel underwater looking for a treasure, the more important having personal experience is.
As a non-swimmer who has never dived, I would never choose a main character who spends important parts of the book underwater because no amount of research will keep those scenes as authentic as they need to be.
NOTE: For more help on writing a fight scene, click on the label "fight scenes."