What Causes Painful Lump Above Navel And Below Ribs?

I have a lump in my abdomen above the navel and below my ribs. I found it about three weeks ago. I am a Navy Vet, I called my pcp al the VA, her nurse told me that the doctor said to stop excersing and start dieting, no exam, will not see me. The lump I can feel, it hurts when you push on it, I feel stuffed after eating a little, I have started belching a lot after eating.