I believe that Heaven and Hell both exist right here on earth. After you die you have to live with the decisions you made while here on earth. For example everyone sins and everyone feels bad about it so my own personal hell would be to live forever knowing that I have sinned and am imperfect.

In short, I don't think that Hell is below the earth, or Heaven is up in the sky, I think that they are in your heart and are based on decisions that you make. I know that I have been through hell after some decisions that I felt really bad about.