Pain just below the rib cage

I have lost 75 pounds since November 09. But the last 3 days my chest right at the center is sore. I am wondering if it could be a hernia,muscle strain or stricther in the stomach. If anybody has any ideas that would be awesome. Thanks

I am not sure if this is realted or not but I went through a phase where my sternum felt like it needed cracking.  I would actually press on it with both hands periodically and it would crack causing a sence of relief.  I also have a hernia just below the sternum that is either painful or itchy.  It is at the top of my scar from the open surgery.