Several years ago, as a result of the culmination of a few injuries in my shoulder and upper back area, I discovered that it could be painful to fish for hours at a time. The only remedy that really worked was daily excercise of the area including stretching and working the right shoulder and upper back. When I abandon my excercise regimen for longer than a week or so, I can be sure that the pain will return and casting a fly rod for any length of time will become uncomfortable.
Dr. Keith Berend, a senior level orthopaedic surgery resident at Duke University Medical
Center in Durham, North Carolina, is conducting a study on flyfishing and pain. This project has come about because of Dr. Berend's desire to meld his passion for flyfishing and his love of orthopaedic surgery. As well, it is an attempt by Dr. Berend to use only the Internet and e-mail as a data source for a medical study.
After watching his father experience pain in his back while wading, Dr. Berend began asking other flyfishers about pain and discovered that it was not uncommon for anglers to experience discomfort. As Dr. Berend so accurately states, "The insane thing about us long-rodders is that we would never let these ailments keep us from performing the art that we so love." Ain't that the truth! I can remember many a time feeling that throbbing in my shoulder but doing everything I could to ignore it, anticipating the next 'fish on!'
Dr. Berend is inviting anyone who desires to participate to simply send him an email to osteofight@mindspring.com and he will send you the questions he would like answers to. Or, if you prefer, you can simply copy and paste the questions into an email and send on your answers. I am providing the questions right here.
I have no idea if Dr. Berend's study will provide any clues to cures for flyfishing pain, but I do know that for most of us, it would take some pretty severe pain to stop us from participating in the sport we love.
The Muncher is a favorite of Ian James for carp, smallies, more. 
Thoughts of a Chicken Rancher. Doc tells it like it is.