I’m a healthy active 42 year old female. I noticed a few weeks ago how uncomfortable it was to drive due to the full feeling under my left rib.  It’s not painful just annoying. I was examined and the pain was at the end of my stomach where it meets my colon.  I had an X-ray which was normal and my next step is a colonoscopy with the tube down my throat (forget what it’s called). It doesn't really bother me when I’m laying down, exercising, dancing (I ballroom dance) or really any other time other than when I’m sitting and relaxing.  My doc put me on an antacid to take for 2 weeks but it’s just making me gassy and giving me headaches and on and off again diarrhea.  Wearing a bra is so uncomfortable