Suggest Treatment For Red And Painful Lump Below The Clavicle

I have had pain in the right side of my chest for 2 months. I have had EKG , chest X-ray and nuclear stress tests with normal results. Last week a lump (for want of a better term) appeared from the bottom of my clavicle extending down about four inches and 1.5 inches wide. It is red and painful to the touch. Just riding in a vehicle will cause pain if I drive over rough road. I am a 51 year old male.