I have the same, it started after(!) I decided that I can see and feel a lump there (and before you start feeling for lumps, two GPs and the gastroenterologist + the ultrasound can't feel anything). I think it could be from tension as it's not increasing, it kind of comes and goes. For me it's the same area, from the top down my side and into the groin area.
Knuckles: how are you reducing your anxiety?