I thought it like there's a perturbation in the nothing-ness, like those virtual particle pairs, but small perturbations successively occurring and building a top of the other could result in where we are presently, at that time those perturbations would've had a more significant affect to the system than it would now. IDK.
Yes some argue it could be extra dimensional forces leaking into our universe. What we really know (from indirect experimentation) is that, quantum fluctuations, are happening all the time, in seemingly empty space. The energy has to be zero, if we tried to add a number to it, it would be infinitely larger then the observable matter which would not make any sense it would break the symmetry so zero energy fits and that gives us a perfect symmetry. I subscribe to the many universes model personally I think it makes the most sense, so I see this universe to be infinite but not boundless, existing inside a flat infinite cosmos with infinite universes that are bounded, and these bounded universe collide into each other universe creating more universes, like bubbles. So the empty space between the universes (bubbles) is part of the cosmos which has zero energy but things are always pop in and out of existence in it.