There are several videos interviewing Dr.Alex DeLuca. I'd suggest reviewing them all. It is very revealing and certainly explains the experience of many people in chronic pain:

http://www.youtube.com/watch?v=OwL02bEq5Dw

PM doctors are under immense pressure now in our country under current regulations and laws and part of the reason that so many in chronic pain suffer unecessarily. The DEA's "War on Drugs" in the 80's and 90's failed miserably. Now they have pointed their sites at those in the pain management field.