As both a believer and a historian of religion, I shall try to answer a few of your questions. The world was created because God, or the gods, depending on which religion's texts you read, because God wanted to do so.
According to the Christian and Jewish scriptures God gave mankind free will, which basically means that there is little point in blaming God for the state of the world, now or at any time in history.
Having free will means we can CHOOSE to be as good as possible and do only good as far as that is possible, or we can choose to be selfish, wicked, evil etc.
If we lived as various religious texts, both Christian, Jewish, Hindu, Sihk, Muslim and Buddhist say we ought to the world would be a far nicer, happier place.
Unfortumately, a lot of people are only concerned with grabbing as much power, money, food, land etc for themselves and don't bother to try and live acording to any religious teaching.
The afterlife in Heaven is something we earn by at least trying to believe in God - if the world had never been created we would be nowhere. We would never have existed and therefore could not be in Heaven, or whatever you want to call the afterlife.