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 which needs to be diagnosed by clinical examination and various investigations.
Your fever,headache ,back pain and increased thirst could be related to dehydration with some bacteria infection which need immediate medical attention.
If you still having
abdominal bloating or distension then you should start some medication like,
1) Antibiotics like ofloxacin with ornidazole
2) Proton pump inhibitors (
pantoprazole or rabeprazole),
3) Take antacid gel like digene or sucralfate,
4) Avoid excess carbohydrates and fatty foods,
5) Avoid oily and spicy foods.
If you still have these problems then you should go for routine blood tests with ultrasound abdomen and upper GI endoscopy if had not done earlier.
Consult to gastroenterologist again and ask him for various investigations to treat underlying cause.
Regards,