Bear,
The current thinking is the big bang is wrong. It's now thought it was the big crunch. The energy was here, but no mass. Just a huge entropy. Then one day the energy slightly compressed. It then collapsed until the space could no longer. Then it bounced back.
The force of the bounce, which is currently still happening, created so much force it created all the atomic elements we have today.
Einstein gave up on quantum physics because he wrongly assumed the universe was no longer expanding.
The big bang was developed by a religious nut, after all.
The morale, never assume shit!
But, where did the energy entropy come from? If all we know about is light to see the past, how do we ever know? Also, the big bounce had to expand for a period faster than light. Otherwise the models break for relativity.
So that raises an interesting question. With enough energy space can expand faster than light. Can we exploit that to find those answers?