"Hell" - "Heaven"

I heard something very interesting these days. I can't remember if I read it somewhere or someone told me this, because of my extremely short memory, but I kept in mind the important part. The question was what ”hell" and "heaven" represent!? Do they exist as afterlife ways of "living" or are they just religious symbols, used to scare people and make them obey some human made up rules? Well, I heard this really interesting theory that really struck me. Hell should not be thought as something that will be but as something that it is. Do you know those people that are really old and sick, see their children and relatives die...but they keep on living, crawling on the face of the earth, carrying their last days as burdens?! Well this is hell. This is how you pay for the life that you have lived. Hell and heaven are nothing but the ways in which you spend your last days and the way you die. When you are old you pick up the fruits from the trees you planted and so very much tried to take care of during life. You pick up the fruits of your own actions. Somehow I find this theory very smart. But than again, what can "hell" and "heaven" represent for those who do not get to live their lives to the end. Those who die as infants or very young in different accidents. Do they pay with their own lives in order to punish their loved ones...or...do they pay for their own mistakes from another life!?