Your soreness could be anything. But, I have just gotten over a soreness in my ribcage area and you know what it was? I was coughing and sneezing about 2 months ago and I either pulled a muscle or bruised a rib. It has just gone away in the last week.
I would suggest to you to put heat in the area that is hurting and I bet it will feel better.
Or, here is another idea. Dr. Schulze would tell you to alternate hot and cold water therapy. Try that!