Pain associated with dark urine can be serious complication. It can be caused by bile duct obstruction
which isnt very rare after such procedures. Your blood tests should show raised bilirubin
level if i am right, but I think that repeated lab and ultrasound
is at least what needs to be done.
Second cause can be abscessus formation or intraabdominal colelction. Especially if you have fever and feel fatigue
Just go to ER if you feel that it is neccessary. If i were your doctor I would do CT scan
and complete lab tests to reule this out. Wish you good health.