With the Big Bang, we don't *know* what the matter was like even nanoseconds before this proposed explosion. It could be that the instant this "infinite mass" was formed it blew up: forming the mass itself causing the explosion. Nothing before the big bang is *measurable*. This by no stretch of the imagination means that before the Big Bang there was *nothing*.
The physics of the big bang say that all space and time were in one spot while the piece of mass was floating around. Which means, 1. Space did not exist. 2. Time did not exist.
The "ball" if you will never came together because all time and space were together. The big bang happened everywhere, becuse everywhere was all in one spot. IThere was never a time before it, since time was all in one spot.
You can't measure anything before, because it didn't exist according to the most commonly accepted version of the theory. It's not something that came together, it is something that happened.
So, where did it come from, what was it doing? The physics answer is that we cannot comprehend it.
According to all observations, all parts of the universe are moving away from each other at an equal pace, and all parts, when moved backwards, come from each other.
My whole point is that physics do nothing more than tell us what we have observed. Just because you have not observed something does not mean it cannot exist.
Scientists argue all the time because they observe the same things diferent ways.
Don't get me wrong, the movie Signs is absurd.
Again, all I am saying is that all science is based on observation and that sometimes our observations our wrong, or contridict themselves.
A better example would be that our laws of thermodynamics both prove and disprove the idea of cold fusion or zero point energy.
It's all where you observe it. We don't know the absolute truth of the matter.