Hello! Thanks for putting your query in HCM. I am a Gastroenterologist (DM).
Pain that is aggravated by food intake may be related to Gastric pathology like peptic ulcer disease especially gastric ulcer
disease, however as Ultrasound abdomen for Gallbladder is normal. So I think it may be related to peptic ulcer disease. So instead of taking antacid take a proton pump inhibitor like rabeprazole
along with a prokinetic agent like domperidone
for reflux symptoms
Other useful measures for your friend are:
1.Avoid fatty meals
2. Don't lie down soon after meals for at least half hour
3.Take small and frequent meals, instead of full meals at a time
4. wear loose clothes
5. If overweight or obese do weight reduction with dieting and exercise
If still pain is not relieved then I will like to advise endoscopy examination to see what is happening inside. I hope apart fro gallbladder rest of the organs like Liver, pancreas are also normal and also there is no bowel trouble
I hope I have answered your query and this will help you. Remain in touch and get-well soon.