Hi and welcome to the forum! I am glad that I can help you.
You want to know the cause of the symptoms that you experience.
The gallbladder may be removed due to two indications: gallstones and inflammation of the gallbladder. Sometimes these two conditions can be found at the same time in individuals. After the surgery, especially after laparoscopy, individuals may experience local peritonitis, because there is leakage of bile in case the clips are not placed properly. In rare cases, between 5 and 40% of the patients that have their gallbladder removed experience postcholecystectomy syndrome, which is charaterized with chronic pain in the upper right abdomen and gastrointestinal distress.
Given the data that you described, it is not likely that the pain may be because the gastric lap-band interferes in the recovery. It is likely that you experience postcholecystectomy syndrome. You may consider seeing a gastroenterologist for further diagnosis and treatment options.
Please keep in mind that I provide medical information only. I am not able to diagnose medical conditions online. Please contact your doctor for further advice and information about diagnosis and treatment options.