For a year now i can feel a strong pulse in my stomach, about an inch below my ribs, in the center of both ribs. i feel it when pressing on area. why?

Probably your Aorta: I suspect you are feeling your aorta pulsating- this is the largest artery in the body and the abdominal portion of it is located where you are describing. It would be a good idea to have your doctor examine you and confirm this though, especially if you are having any abdominal or back pain as that could signify a problem with it.