Looking for a short story I probably read as part of an anthology in the early-mid 1990s.
The protagonist was a man living in the 'present', who suffers permanent pain from an injury (possibly involving diving or the water?), to the extent that he keeps a bottle of powerful painkillers next to his bed.
One day he wakes up pain-free, and finds himself in a utopian future. He meets a woman who introduces herself as the wife of the man whose body he currently inhabits. She explains that they are able to travel in time by switching minds with someone else.
The future is essentially perfect; there's no pain or disease, and people can swap bodies as needed to resolve medical issues. The protagonist sees this as effective immortality.
He then returns to his own body, and finds the pain is all the worse and harder to deal with for his time away.
The switching keeps happening, and he finds himself falling in love with the woman and the future. She complains that her husband is becoming bitter and cruel after his trips into the past, implied to be because of the pain he is experiencing.
The man plots to kill the time traveler by poisoning the pain pills, intending to kill his own body and 'trap' himself in the future.
After the next trip, however, he wakes up back in his own time but in a totally different, pain-free body. That is his last trip.
I think that, at the time I read this, I probably had not seen Quantum Leap. I certainly didn't make the connection to the similarity between the stories. That would suggest this was late-80s or very early-90s.
The man referred to his pain medications as "the dope" fairly frequently.
The pain was a huge element in the story. It's the pain, and the hope of being free of it, that drives most of his actions.