how do you know if u have an ulcer or just scar tissue that is causing pain

I have been getting pain every so often in my navel area.  i feel like cramps.... and no not the type of stomach cramps that makes u feel like u have to go to the bathroom.... any ideas??? it only hurts in the navel area 

I knew I had an ulcer when I would sip some milk and the pain would go away.  I also discovered if I would eat yogurt and the pain would go away also.  I just starting taking Prilosec.  When I saw my doctor a week later he told me I did the right thing when I began to take the Prilosec.

I take prilosec every day and i still get the pain every blue moon.  

Endoscopy will tell you for sure.