Why should hell be taken literally?

I completely agree with you. "Hell" isn't a literal place with external torments such as fire, lava, etc. But rather hell is a separation of the person and God by the person's own choice because of feelings of guilt in one's own conscience. It is in a sense, spiritual death. This doesn't mean the spirit dies, but rather the person is cut off from things that are spiritual and good in the sight of God.