I see that Physicist has arrived, so if I were smart I'd shut up now.
OK, I'm not that smart. That I can recall from reading the layman's treatments of cosmological stuff, you have the quantum hiccup idea and the multiverse idea. The former says that the universe is a quantum fluctuation with zero total energy. The latter says that some part of a meta-universe sort of collapsed and popped out into our Big Bang to form our universe.
That's interesting. I think I remember reading a sci fi story many years ago that had us in a 3rd big bang after a series of expansions and contractions. Nevertheless, they're all appear inadequate in addressing the something from nothing paradox.
Don't clam up on my account; you're doing fine, and I'm way too busy to field all of the questions today.