Always trying to find differences and level non white skin humans in a disadvantaged level. Not fair. As far as pain goes I do agree, experiencing trauma does affect the tolerance to pain. I went thru a lot of dental treatments as a young girl. When it comes to dental work I tolerate way better now any procedure. When I was pregnant I did not use anesthesia at all and had a vaginal delivery. The pain for me was doable. And many other situations where no pain killers were used. I am not black, I am Mexican and have white skin. I just wanted to make the point that yes, trauma at early ages sort of tough us although I would not generalize. I am no expert and have not research about this topic but I can only share my own opinion, based on my own experiences.