knot on my chest , bottom of rib cage
 

4 years ago I had surgery for heital hernia. I now have a knot about the size of a quarter at the bottom of my sternum. It is not sore and does not hurt, but it still concerns me. Could this be something caused by my hernia ? Even though I had the hernia repaired my family doctor says my hernia is back.Can you give me any idea what this knot is?