Was there space before big bang? Or who knows there might be different heavenly bodies that we might not perceive?
"What happened before the Big Bang" is like asking what Alexander the Great's phone number was. It's a nonsensical question.
Space and time began with the Big Bang. "When" and "where" began with the Big Bang.
The answer to this questions turns out to be a "yes". The big bang is a sudden rapid expansion of space, so yes, there was space before the big bang. To understand more, check this vulgarization video by MinutePhysics who corrects some misconceptions about the BB, since you seem to not know the Friedmann-Walker-Robertson-Lemaître metric.