What Causes Belching And Tenderness In The Ribcage?

Hello, for the last week or 10 days I have been passing yellowish floating stool and have had severe bouts of belching after eating no matter the food. The discomfort is not associated with any pain bit the belching is excessive and deep. I have tenderness when I press just underneath of the center of my ribcage. My bowel movements have been pretty regular, once daily. My diet has been protein and fat heavy though. I have had a lot of stress at work and have problems sleeping for more than 4 or 5 hours per night for a long time now. I m moderately active, try to do several sessions of exercises daily and try to walk at least a few kilometres per day.