Well, we can always guess. But I truly, honestly don't know. Where did all this come from? How did it come to be? Where are we? What are we? What is this whole place we're in? Is anybody in charge of it? Did anybody create it? Some people tell all kinds of wild stories about it, none of which seem to have a ring of truth to them, but interesting just the same. They're all guesses, which is all we can do at this point.
Perhaps in the future, we will develop better technologies and better instruments of observation that will allow us to learn even more about the state of our reality and what else may be out there in this universe - or perhaps multiverse. We know more than we did 100 years ago, and I'm hoping we'll know more in another 100 years (although I don't expect to live that long). And even that may not really solve any deeper questions of existence or explain "why are we here."