I Had Open-heart Surgery To Correct A Right Anomalous Coronary

I had open-heart surgery to correct a right anomalous coronary artery July, 2014 with what appeared to be a decent recovery--stationary bike riding, running after a 2 month recovery (running many miles over the past 39 years). Over the past 2 months, I have experienced decreased aerobic performance, weight gain (with reduced calorie consumption) and, just recently, swelling in upper abdomen, left side just under pectoral AND what feels like a small "lump" or nodule just under the skin about the size of a dime. Any thoughts?