I Had Malignant Lymph Nodes Push On The Outside Of

I had malignant lymph nodes push on the outside of my duodenum until it was closed. They inserted stent to open it up. Everything felt fine for about a week then I started getting stomach aches. After 3 weeks I called the doctor and said I couldn't stand the discomfort any more. I asked him to prescribe something like a stomach tranquilizer which he did. I also started taking Zantac. It seemed to help for about a week but now the stomach ache is coming back. I get an endoscopy tomorrow morning. If they can't see any particular reason for the pain, what am I going to do?