In the Old Testament heaven seems merely to refer to the sky.
It was God's abode.
But it does not appear to be the destination for ordinary souls.
Elijah ascended into heaven (the sky) in a fiery chariot.
But this was a special event. It did not happen to others.
My concordance records no references to hell in the Old Testament.
Instead it refers to Sheol.
Sheol would appear to be under the earth and was the habitat of souls after death.
Here the departed lived a shadowy existence something like the shades of Hades.
But it was not a place of eternal fire and torment.
The first references to hell appear in Mark's Gospel - written about 60-70 CE.
This appears to have developed from the idea of eternal life found in Jesus.
Jesus ascended into heaven and prepared a place for his followers there.
So the logic goes that unbelievers or heathens must go to a place of eternal punishment.
If there is a heaven that you can go to then there must be a hell also.
Thus hell was born.
But hell is totally out of character for the loving God of Jesus.
It is very much the stick to heaven's carrot for those who have no faith in human nature.
It is more to do with controlling sinful humanity than understanding God.
So, just as hell appeared after Jesus' death, so may it disappear after the end of Christendom.
The time has come for humanity to discard the baggage which grew up around the Christ and settle for the Love of God and forgiveness for all.