Yesterday, I experienced a sharp pain on my front left rib under breast. I couldn't bend down or breathe without it hurting. I went to lay down thinking it was just a spasm or something, and it went away. A few hours later it was back. Today, when I push on my rib it hurts like a bruise and has a small knot on it. It doesnt hurt as much to breathe in now. It more or less feels like a strained muscle or ligament around my rib now. I am just wondering what the knot and pain are caused from.......any ideas?