What Causes Recurring Pain And Swelling Below The Ribs?

I seem to have recurring pain in my right side....just below the ribs. Feels like something is swollen. Recently completed the new Hepatitis medicine, and killed the virus...but now have a moderate to severe pain frequently. Some have suggested gallstones. Sometimes I get short of breath, nauseous, and it feels like something inside is going to burst. Often with intense hardness in the middle of my sternum....very intense.