Here's a read that I received on facebook from the RSDSA. It touches on the subject of this thread. If the read is too long check out the last paragraph.

"Why Does Chronic Pain Hurt Some People More?
Brain Research Reveals New Clues
Brain research reveals new clues about the reasons behind different physical reactions among those who suffer injuries.

By Shirley S. Wang

Why does pain from the same type of injury linger in some people but not others?

Genetics and brain-based biological factors are the latest frontier of research on chronic pain, along with personality traits, coping strategies and life experiences. The question is a riddle researchers have been trying to solve for decades.

*edit*
sorry there is copyright on original article (http://online.wsj.com/article/SB1000...wsj_india_main)