The Christian idea of hell seems partly to have come from the Greek Gehenna from Hebrew Gehinnom, the valley outside Jerusalem. This became a symbol of condemnation because child sacrifices had been offered there (2 Chronicles 28:3 and 33:6). “They have built also the high places of Baal, to burn their sons with fire for burnt offerings...
The Christian idea of hell seems partly to have come from the Greek Gehenna from Hebrew Gehinnom, the valley outside Jerusalem. This became a symbol of condemnation because child sacrifices had been offered there (2 Chronicles 28:3 and 33:6). “They have built also the high places of Baal, to burn their sons with fire for burnt offerings unto Baal, which I commanded not, nor spake it, neither came it into my mind: Therefore, behold, the days come, saith the LORD, that this place shall no more be called Tophet, nor The valley of the son of Hinnom, but The valley of slaughter.” (Jeremiah 19:5-6)
As Sheol, hell is just lying dead in the grave, and not selected for eternal life in the new theocracy or kingdom of God.
But there is also the picture of darkness and unquenchable fire (Mark 9:43/Isaiah 66:24 and Matthew 8:12). "... cast into hell, into the fire that never shall be quenched: Where their worm dieth not, and the fire is not quenched." and " But the children of the kingdom shall be cast out into outer darkness: there shall be weeping and gnashing of teeth."
And in the parable of Lazarus and the rich man, it says: "The rich man also died and was buried. In hell (Hades), where he was in torment, he looked up and saw Abraham far away, with Lazarus by his side. So he called to him, 'Father Abraham, have pity on me and send Lazarus to dip the tip of his finger in water and cool my tongue, because I am in agony in this fire.' (Luke 16:22-24). And there's the Lake of Fire in Revelation. Greek culture was plainly influential in the eastern Mediterranean at the time, so would have been adopted and adapted among the beliefs of the time.
Apart from this there's the imaginative picture given in Dante's Inferno.
The more modern re-interpretation of hell as an emotional or mental state, or the unhappiness caused by the absence of God, seems to be re-interpretation by church leaders embarrassed by the obvious mythical nature of the belief. But emotions are caused by chemical changes in the brain, as is our mental state, so after death these just won't exist.
Like all myths, people re-interpret the meaning to fit in with what is believed over time, and the later beliefs are read back into older scriptures to re-interpret them in ways that the original writer or prophet could not have meant.
But being myth, we know that we don’t have anything like hell to fear.
Paul explains in Romans 5:12, "When Adam sinned, sin entered the world. Adam's sin brought death, so death spread to everyone, for everyone sinned." But he blames women more: "...I suffer not a woman to teach, nor to usurp authority over the man, but to be in silence. For Adam was first formed, then Eve. And Adam was not deceived, but the woman being deceived was in the transgression. Notwithstanding she shall be saved in childbearing, if they continue in faith and charity and holiness with sobriety." (1 Timothy 2:9-15). The Adam and Eve story was a myth that tried to explain how death, toil and other woes came into the world and why we aren’t immortal; and like the Greek Pandora myth, a woman is blamed (and by extension, in a patriarchal society, all women).