stomach aches when lying down

I am a little over 3 weeks post surgery and still on the liquid diet. For the last week, when I go to bed at night, my stomache feels an instant almost "hungry feel" when I lie down. That turns into a pretty bad pain that runs from my stomach up to my diaphragm. One night I got up and ate 1/2 a yogurt and that seemed to help enough to let me sleep. It's just odd I only feel it when I lay down. Has anyone else had this problem? ???? :rolleyes2: