I am sorry to hear of your situation. I can relate entirely; I also wound up with C diff after surgery. Im reading alot of your liver, stomach, and gallbladder, and the normal testing of them, (except for elevated liver enzymes) but I have seen nothing here regarding your pancreas. And, the pancreas is a huge organ that sits in the top left and right quadrants. If you have not been assessed for pancreatitis, an inflamation of the pancreas, I do reccomend you discuss this possibility with your physician.
Signs and symptoms are the pain you describe, but in addition there is often nausea, fever, and the pain gets worse after food or drinking alcohol.
Pancreatitis can be found by doing blood work to check for levels of the enzymes amalase and lipase...in addition, with pancreatitis, liver enzymes can be elevated, and calcium levels can be decreased.
Here is more information regarding pancreatitis: http://www.mayoclinic.com/health/pancreatitis/DS00371/DSECTION=1
I do suggest discussing this with your doctor. If the pain becomes wracking and severe, it may merit a trip to the ER to be sure nothing horrid and acute is happening.
I hope I was able to help,