Hi, My Son Is 11 Yrs Old And Has Been

Hi, my son is 11 yrs old and has been vomiting bile. He will vomit bile just walking too much or playing with his brother. He had an abdominal ultrasound done in November of 2015 and they seen a 5mm growth in the wall of his gallbladder. His specialist prescribed him omeprizole and it work a little bit but not alot. They have done numerous test and labs and still can not diagnose my son. Are the two connected? What else can be done?