I remember sleeping on my belly as long as I could remember. Recently I have been having pain in the belly when I sleep belly facing down. When I take a short nap for about one hour with my belly facing down my stomach hurts and later have to urinate to relive myself from the pain. It takes about half hour to get the pain relived completely. Although I stopped sleeping on my belly completely but I feel its important to know what the problem is. I occasionally roll myself off in the sleep and have the same pain.