Tramadol
"I have a 35 year old whiplash, so the pain is fairly chronic, and settles in my neck but moves into shoulders and mid back. My pain seems to be skeletal and muscular.   Tramadol is excellent at handling the pain.  I want it to always work, so I never take it until after the pain has started.  Sometimes I can go 2 days without taking a pill; other days, I have to take 2 pills in one day."