I have thought and thought and thought about this -- trying to get past my knee-jerk angry reaction to Western Medicine and its relatively hysterical reaction to visible physical disability combined with its more low-key and some might even say unconcerned reaction to pain.
Perhaps it's genuinely more difficult. Perhaps it was easier to invent prostheses (some that are nearly as deft as I am), wheelchairs, crutches, grabber/extenderss, hand controls for cars, power chairs, and electronic wheelchairs that OBEY YOUR THOUGHTS than it is to come up with reliable pain relief. Seriously -- maybe it is. I am not a chemist or engineer.
Or maybe our medical minds (and donors) just don't think chronic pain is particularly important. I don't really know.