I have been having lower back pain for some time now. In the last couple of months I have had stomach pain. I feel like there is something sitting under my ribs and pushing up. The only way to get relief is by sitting up straight. I was engaging the lawn mower blade one day and something popped out from under my ribs causing me great pain. I had to sit up straight and kind of push it back under my ribs. The other day the pain was real low as if something wanted to pop out.
Are you able to feel the structure which is coming out?  Because it can be a hernia.  My advice to you is that you should get ultrasound of your abdomen.  This will give us idea if anything really coming out of your abdomen.  Also, I would encourage you to avoid spicy or heavy protein diet.