Does gallbladder sludge cause severe back pain? and starting to feel nauseous

POSSIBLY: Gallbladder sludge is basically very tiny stones and granules. Sludge is the precursor of larger stones, and certainly can cause similar symptoms. So, if you have nausea , back pain or right upper quadrant pain, especially after fatty foods, it is quite possibly the cause. I suggest you discuss this with your doctor and surgeon. Good luck.