Our cosmology teaches that the hell-realms are not permanent, but those that are incarnated there are having a much worse time there than any kind of suffering we can imagine here.
Fwiw, our cosmology teaches also that the god-realm is not permanent, either. To be removed from all the suffering that exists in the lower realms does not help, but only seperates oneself from contributing to the welfare of others. I believe that going to heaven does nothing more than satiates the ego...........which is why we call it the "god-realm", where all one's desires and wishes are fulfilled.
The human realm is the only avenue an entity has to become fully realized and to attain enlightenment. I've said it before and I'll say it again - every single one of us here has done something very right in a former life to be born human (which is why we call it "precious human birth"). Our human faculties that allow us to experience suffering without becoming attached to it is the one way for us to achieve buddhahood and to help all others.
Hell has only suffering, and one is drowning in it there. Enlightenment is impossible because there is nothing but suffering there.
Heaven has no suffering, and one is completely removed from it. Enlightenment is impossible, therefore, because one does not fully understand the reality of suffering and hence can't be engaged in helping others.
This is where the Buddhist law of impermanence always makes sense to me. Everything dies, and is reborn anew. This is true no matter what realm one finds oneself in.
Peace,
Mystic