My doctor said he never heard of stenoclvicular joint grind.something in the area is grinding and gives me discomfort. am i imagining this then?

SC grinding is real: You are correct. It is a known condition to have sternoclavicular joint grinding. It may come from arthritis in the joint (bone on bone), a small cartilage tear in the joint, or from some laxity in the joint. The standard treatment is to treat the symptoms with activity modification, physical therapy and anti-inflammatory medications. Injections or surgery are very rare on this joint.