Have you had an MRI of the area? I would honestly make enough noise that your doctor has a second look. Sometimes you really need to stress to them that you are truly in considerable pain - and that your medical history will prove you're not a hypochondriac or opioid addict.
I haven't had exactly what you describe, but I will say that with my own experience, gallbladders and their removal aren't simple or even cure the issue. I had my gallbladder removed in 2015, years before my WLS. I had a terrible gallstone attack that landed me in ER. Since then, I have had, on and off, gallstone-like attacks despite no longer having a gallbladder. Same sensation. Same building pressure that can bad enough that I have to lie down and just groan the pain out (I live in fear of it happening while driving). I get very sore right under my right rib where my liver is. Then it goes away again within a few minutes, sometimes less, depending on the severity. My gallbladder surgeon was also my WLS surgeon, so I've been able to tell him about it the last couple of times I've seen him. We're keeping an eye on it, and if it gets worse we'll have to talk options, however he's warned me that the "cure" can sometimes cause even worse issues, so I'm unlikely to choose a surgical fix. Apparently what I have can happen - sorry I don't recall the details (I was talking to him right before he did a gastroscopy on me so I was dopey), but from memory, some people can continue to have "attacks" because of new issues with the bile duct leading from the liver.
Anyway, that's a long winded way of saying "chase this up because post-gallbladder-removal issues absolutely happen".