I am about 4 weeks post op and I am beginning to have upper back pain, between my shoulder blades. I know this is a sign of being full, but I'm back on liquids due to stacking. What could this be?

There are a number of people post-op who develop gallstones after bariatric surgery. When I had my gallbladder out in 1973 (back when the still cut you half in two) my symptoms were similar to what you are describing: Back pain under my right shoulder blade felt like someone was stabbing me with a bowie knife and twisting it around. This one is worth calling your doctor about.

What is stacking?

Stacking is when you eat more than your new tummy can hold and the food backs up in to your esophagus.

I have back pain since surgery, I was told that our body is adjusting to the weight change. I hope it gets better! Im 2 months out.