I went to my GP March 28th about a hard mass,  in between the size of a grape and a golf ball, that I noticed about a month ago under my left clavicle. It was painful now and then. I put an ice pack on it and take Tylenol. He had me take an ultrasound today and they didn't tell me anything other than it was growing on my muscle under my clavicle. I looked it up and sarcomas and lipomas grow on muscle. So I guess we'll see. He said he would probably send me to a specialist.