Around Christmas, I was reaching into the closet to hang up a garment. I felt an excruciating pain about an inch below my collarbone. It felt to me like a sudden muscle spasm or a knot in my muscle. It continued to be very painful, and I tried stretching, etc, to relieve it. It eventually subsided, but it recurs if I reach up, out, or various sort of sudden movements like reaching or stretching my arm up or out. When the pain occurs, I have found that if I lean over for a bit, it feels like the knot in my muscle sort of dislodges and relieves the pain. When I push down in the area of the pain, there is nothing out of the ordinary; no lump, mass, hard spot- nothing. Any earthly idea what this could be?