This is not a story of BDSM.
I was thinking of the physical discomfort and possibly pain experienced by someone climbing or scaling a mountain. See photo below.

I was thinking to myself today: what goes through the mind of a mountain climber as he scales a rocky mountain? Does he climb a mountain with no discomfort at all? In other words, as he’s climbing a mountain, does he feel amazing, like having a massage or even better, having sex? As I ain’t no climber, I have to guess, no. He probably feel like shit at times or all the time. He probably has to have a rest and catch his breath after a challenging section of the mountain before he continues. He might even fall or lose his footing on the way up.
Why the hell does he still want to reach the top of the mountain (assuming that his destination) when the journey is arduous, make him feel like shit, requires loads of practice and preparation, etc. I suppose more importantly, if it is part of the process to feel like shit in order to reach our goals, maybe we should expect it as part of the journey towards our version of success, what that may be. For example, if our mountain top is to be a parent but we are physically not able to, part of the journey is the discomfort, disappointments relating to IVF and/or alternative methods. If we want to be a professional writer, perhaps it is to work multiple jobs if we need that financial security and give up socialising and other hobbies.
Maybe no pain no gain does describe the journey to what we want. Unless you are one of those lucky bastards (fuck you).