Michael, that stomach pain sounds very similar to what I had, and it was about that same timeframe - 3 wks post-op. I noticed it seemed to get worse in certain positions (like sitting in the recliner, which causes me to be semi-bent in half in that area). It was right at the bottom of my ribcage, and/or at the very top of my abdoman - right where I think my diaphram is. They checked me for fluid buildup a few times too (I was back in the hospital at the time due to some irregular beats - which by the way, I kept thinking might have been triggered by that pain). I never had any fluid buildup. They attributed it to normal healing - you're stretched pretty good during surgery, especially at the top and bottom of the incision. If it's the same pain I had, it'll eventually go away, but might take a couple more weeks. But you never know if it's the same pain or not, so best to get it checked out if you haven't already told them about it.