After Aerobic Exercising, I Experience A Constant Tenderness To Discomfort

after aerobic exercising, i experience a constant tenderness to discomfort only on my left side rib cage area. has been this way for 4 weeks. today i feel a slight bulge where it is most tender, if i press area. Am i aggravating an organ or causing a potential problem? seems to be more than just sore muscle from workout.