The universe didn’t explode. It’s believed it expanded from a pin point. Think of the universe 1 second before the beginning expansion, as a point. Suddenly expanding rapidly in all directions, like a giant balloon inflating....The universe expanded out from a microscopic point, many believe, and much of it appears to be expanding to this day.
No ones knows what caused this expansion.
No one knows where if came from. Some believes there are multiple universes/dimensions..Or multiverses and the theories go on from there.
But a pin point of what? What pinpoint could contain the mass and energy needed to form the universe?