^^ First: Welcome to DV's, AnnaMae!
That's an interesting question, and one I've sort of asked myself, because a similar thing happens to me very often (you can read about it here, if you're curious).
I think the first thing that you might consider is that you actually are in all of your dreams, even f it doesn't feel like it. You really must be in them, or else you wouldn't be able to witness them, from any perspective. And you really must be in them because they are processed by you and occur within your own mind, so in a very real sense dreams are You, no matter how strange or distant they may seem.
There are no rules that define how the content or experience of dreams occur; it could just be that your brain, for whatever reasons, has wired itself to present dreams in the manner you describe, and that wiring is pretty stubborn.
One of the excellent things about lucid dreaming, though, is that you can explore or attempt to change your dreams' "standard" presentation, getting yourself involved in them....if you haven't yet tried it out, this could be a good reason to do so. Who knows? Once lucid you might be able to confirm that everything I said was wrong, and you really are watching someone else's dreams from a distance!
Also, it's very cool that you are putting your dreams to work for you by making stories from them!