Very interesting.

As far as the theory of the big bang is, of course it's a singularity. We don't really understand everything though. It would seem like some massive singularity exploded for some reason. Maybe there's something that overcomes the power of gravity once all the mass is there. Maybe it was ripped apart by the same force now expanding the known universe. And what is that force?

Whatever it is, I like that your hypothesis has a cyclical sort of end to the seemingly endless expansion into nothingness. The universe expanding so far that everything just flies apart just feels wrong. Like that's the end? If it turns into energy and then coalesce, then that feels more fitting than just an endless expansion and death.