What experiences in Poe's life may have inspired him to write "The Pit and the Pendulum?"
I had to edit your question down to one question according to enotes regulations. Key to this question is understanding the way that this story has been interpreted symbolically. Some have argued that the ingredients of this disturbing tale are richly symbolic, suggesting that the pit may represent death or Hell, the pendulum may represent time or the Grim Reaper, and the trumpet blasts may refer to Judgement Day. Thus some critics argue that this is a story of a man who dies and almost loses his soul in the pit of hell but is saved at the end by God.
Whilst the answer to your question will be based entirely on speculation, as we have no way of proving if Poe was using his own life experiences to create this tale, certainly his own exploration of the "dark soul of mankind" resulted in some disturbing effects on his own life, not the least a serious drinking problem and a humiliating poverty. The death of his beloved wife triggered a period of even greater instability in his life, giving him enough experience of being "lost" to base this story on.