Most of the pain that I experienced was from gas pain. It was very painful at times, particularly the first 2 or 3 days after surgery.
Every time I saw a nurse I was asked if I had passed gas. Had no idea gas could hurt like that, but it sure did. Was told that the openness of the surgery leads to air being captured when the patient is sewed up.
Not sure if this is the problem you are experiencing, but thought I would share.
Prostate removal November 2007
Gleason score 9, PSA 14
Biopsy result - 9 of 12 sticks showed cancer
Despite high Gleason score, cancer was confined to the prostate
Unrelated surgery January 2008 delayed incontinence recovery, which is now showing good signs of improvement (1 to 2 pads a day)
Began using Osbon Erec-Aid Esteem manual pump for therapy mid-February 2008
Begain using Viagra 3 times a week December 2007 to stimulate blood flow