I'm a 41 year old male. Smoker for 25 years. I've had upper stomach pain for about 2 and a half months. At the beginning there was also mild chest burn. I had a blood test done to rule out h pylori. It came back negative. I've been on Pantoprazole for about 2 months now. When I tried to come off the medication about 2 weeks back, my pain came back. The doctor feels it is probably gastritis. I plan on asking for an upper endoscopy. Since I'm negative for h pylori, what else can be causing this. I don't drink alcohol. Any feedback would help. Thank you.