Well, it's not explicitly stated. But you can infer that a significant period has elapsed, as Montresor recounts events with a sense of distance and reflection.
It could be that Montresor wants to show how he was wronged and that his revenge was justified. Or perhaps he just wants to share a dark tale for the shock value.
The recipient of Montresor's tale is ambiguous. It might be someone he considers a confidant, or it could be a symbolic act of sharing his burden with an imagined audience to unburden his conscience.
Maybe he wants to get something off his chest or seek some kind of validation.
There's no clear indication in the text about who Montresor is telling the story to. It leaves it up to the reader's imagination.
Montresor is telling this story to an unnamed person. We don't get a clear identification of who this person is in the story. It could be someone he trusts, or perhaps he's just unburdening his conscience to a random listener.
Montresor might be sick due to the inner conflict and remorse. His conscience could have finally caught up with him, causing physical symptoms. Another possibility is that the intensity of the emotions during the events at the end of the story overwhelmed his system.
It could be to a close friend or confidant, someone he trusts to listen and understand.
Montresor is vengeful and calculating. He plans his revenge on Fortunato meticulously.
One possibility is that he could be telling his story to a priest. In the context of seeking absolution, Montresor might be confessing his dark deed. Priests are often the recipients of confessions, and Montresor, burdened by his conscience perhaps, could be unburdening himself to a man of God.
It might be. If the story is interesting and engaging enough, it could be passed down. Hunters often have unique experiences that can be fascinating to others, especially if they involve rare animals or difficult hunts.