It's pretty simple. While my answer is to another question, i still hope it can give some indication for you ;)
Question.
Where in the universe did big bang happen?
Answer.
Imagine the universe as a balloon. What we know as the outside of our balloons doesn't count here, so ignore that. The beginning of big happened everywhere, it was when the balloon first inflation started. since then it have expanded, to fill more than it's beginning, but since the explosion was everywhere in the beginning it would have happened everywhere now too.
Of course you can start believing in religion, AFAIK it gives less headache ;)