I Am A Diabetic. I Take Insulin. While My Blood/suar

I am a diabetic. I take insulin. While my blood/suar is under control, I have abdominal pain and bloating. I tend to burp and have flatulence. I do not over eat, yet feel full with a small amount of food. I have had this for about a year now.
I have had colonoscopy, CT and abdominal sonograms, I am told all appears normal. Can these tests and doctors be missing something.