This one is mind boggling... I've heard it might be a "ventral hernia"?
I haven't found a pattern for the cause of pain... but it so crippling I know during one more attack, I may have to be rushed to the hospital.
I had my gall bladder removed over 3 years ago, but for the last 2 years, shortly after a meal... I can feel the pain growing in my stomach... direct center. A hard, painful bulge grows just over my belly button and slowly moves downward... all the while causing excrutiating pain. It usually lasts for about 3-4 hours... and I try to nap during this (if possible) to relax and ease the pain.