My personal belief is that Heaven and Hell are the same place.

Wherever our souls go after this life, before we reincarnate, is perceived differently by everyone.
If we racked up a good amount of bad Karma/Karmic debt, we see it as Hell. I don't mean the firey hot place with the devil as it's typically depicted; I think it's just a negative, unhappy sort of thing, where we experience all the unhappiness and pain we caused in this lifetime so our mistakes are pointed out to us, then we reincarnate and are instructed to make up for those mistakes.
If we made good on our Karmic debt or something, then we perceive the next place as Heaven. Again, not the typical depiction of it - probably just something like peace and happiness and oneness with love. Then we reincarnate to spread those feelings and learn what we still need to.

These are just my own ideas. I don't know if this is a common belief or if I'm totally full of it, but it feels right to me right now.