Hi,
Welcome to health care magic,
Stomach bloating is caused mainly because of air swallowing known as erophagia.
The other causes are
irritable bowel syndrome,dyspepsia, constipation ,
celiac disease,sprue,bowel obstruction which needs to be diagnosed by clinical examination and various investigations.
If you already took gas x and still having
abdominal bloating or distension then u should start some medication like,
proton pump inhibitors (
pantoprazole or rabeprazole),
Take antacid gel like digene or sucralfate,
avoid excess carbohydrates and fatty foods,
avoid oily and spicy foods.
If you still have these problems then u should go for routine blood tests with ultrasound abdomen and upper GI endoscopy if had not done earlier.
Consult to gastroenterologist again and ask me for various investigations to treat underlying cause.
Regards,