Yes, my youngest son doesn't feel pain, as he has sensory processing disorder. He has broken his wrist, his lower arm, his leg and his ankle... I think he doesn't land properly because it won't hurt. When he broke his leg, he kept trying to walk on it and informed me it was probably broken as it kept "clicking" and couldn't support his weight.
It sounds good... but really isn't helpful. He also can't tell when he is having an asthma attack, which is a worry.
just so, I wondered about that too. If they could tweak our DNA so we could feel some discomfort rather than agony, that would be helpful - enought o alert us that something's not right.