Heaven and hell, in my opinion, are the continuous state of your conscious mind. That constant, never-ending stream of thoughts is called karma. It is composed of the cumulative effects of your conscious mind's deeds (thoughts) up to this point, which determine your conscious mind's current state. This, in turn, serves as the foundation for the karma that will determine your conscious mind's future state.
Therefore, you must make deliberate, aware efforts (energy) to steer your karma in the direction of your choice outside of your mind stream's pre-designated flow path in order to change the direction in which it, karma, travels.
As Jesus Christ said, the kingdom of heaven resides within you. So does the kingdom of hell also reside within you.
