Hello. I am a 20 yr old Female. Last Thursday me and my friends were goofing off and i did a back bend. I don't usually work out or anything. So the day after i done it... I had this bruised type feeling about an inch under my right breast. I started feeling around for whatever it was... and noticed a knot. It is pretty hard. and it does not move. On the other hand though.. it was sore for a couple days but not anymore. I googled for it and found something that said it could be a pulled rib muscle. But i dont know. It doesn't hurt to move,cough,sneeze,or bend over so i dont know if it is a pulled muscle. I just need someone to answer this for me.. Does this sounf at all anything like a pulled rib muscle? Theres still a knot there.