READ THIS BOOK..
Seriously, I couldn't put it down.
The Great Divorce by C.S. Lewis is incredible for the way it presents every concept within its beautiful framework.
He depicts the idea that "the gates of hell are locked from the inside", in that people who have rejected God are not only refusing heaven in the literal aspect, but more-so in that they refuse to be the creature God intends for humans to become. They reject His perfection, holiness, and mercy, and are therefore left with no other choice but their own death. Fascinating story.
It is a fictional story, but the concepts are mindboggling.
So, if any (or all) of this has confused you, please just allow me to say one last thing:
Go read it, and you will (possibly, hopefully) understand!
Ciao for now