17 Year Old Having Severe Abdominal Pain, Nausea, Vomiting. Done X-ray, Endoscopy And Colonoscopy. HIDA Scan Showing Mastocytosis. Need Surgery?

My daughter has been having severe abdominal pain , nausea , throwing up, etc. for about a year and a half. She has been through so many test (ultrasounds, extreme amount of blood work, xrays, endiscopy, colonoscopy (which found she has Mastocytosis---which she is now on meds for) and recently had the hida scan done. Her percentage was ejection fraction was 85%. Her GI doc says this is normal, but after reading throughout the internet, I have read that is high and she has an overactive gallbladder, and she should have it removed. She is 17 years old. Your thoughts, please.