What Causes Recurring Abdominal Pain With Inflammed Duodenum?

I am Vincent and I was having pain in my stomach immediately after eating and in November 2014 I went to hospital and did endoscopy and it was discovered that I had Helicobacter in my stomach. Then I took the medicine prescribed by the doctor. After sometime I repeated the same test and I was told that the bacteria was no longer there. Well since then I have been having problem with my stomach. I have taken Omaprazole for a long time and now I am tired. I have gone to several doctors who advised that I should stop eating food that contain gluten and acid. But until this moment I still have pain in my stomach and even at times it radiates at the back. At present I don t take milk, coffee in fact a whole lot of food. Please help me I am gradually dying. I can only eat pasta and spaghetti that don t contain gluten. I try to eat small amount of food regularly even at mid night. The last endoscopy I did in September, the doctor said I don t have ulcer but there is inflammation in my duodenum. Having stopped eating everything that contains gluten, acid and lactose, I thought there would be a change but the problem remain the same; pain in the stomach, feeling full in the stomach and tiny white particles in my stool.