Pain science is real weird.

This is a bit reductive, but one of the theories of pain is that it's entirely neurological, essentially meaning that pain doesn't actually correlate to physical harm to the body meaningfully. The other thing this means is that we tend to build these neural pathways the more we pay attention and hyper focus on any given body part. Compounding on this: the less outside stimulus, the more likely it is that we will have the ability to focus on the minutia of our internal processes in the first place.

Again, this is somewhat reductive as a measure of explaining pain, but it is probably partially correct.