Bruised Collar Bone Near Center Of Chest With Knot, Itchy, Sore, Burning Sensation, X Ray Reports Normal

I have a bruised like area below my collar bones near the center of the chest with a knot that doesn t really move. the brusied areas been there for about 2 weeks now but the knot showed up just over a week ago. It has gotten smaller but hasn t gone away. There is some itching to it and sorness. When the knot first showed up there was a little burning sensation. Had my labs do and they all came back good and xrays showed nothing. What is it and why won t it go away? No white center and no puss in it.