This is normal for a knot to be there where the skin and as they call it the meat of the site has been stitched , it will be a knot for some time , and the pain will go away after a week more or less , and you will have pain there , for awhile, did your doctor give you pain meds, if not talk to him about this, and when you bend over you are puling at the site with your body muscles, and it will get better


