Talk to Gastroenterologist on Abdominal Pain

I feel severe pain in my belly button and left side in night if I sleep 3 hours continuously. After 3 hours I have to wake and walk for 30 minutes. I burp a lot. I disturb me a lot. Doctor told me that u have fatty liver and sugessted tab. Eveyan and tab. siliver daily. But its not working. The problem become severe if I eat dairy product like yogurt or milk in the evening or even black tea with milk. Kindly suggest me some medicines.