Two months ago, out of the blue, my right clavicle and neck became very painful.  I went to my physio who told me it is arthritis and arthritis can present itself over night.  My right clavicle is larger than the left and I also have obvious 1 inch bumps.  Also my right shoulder blade is painful.  The physio said to stop slouching, tuck my chin in and elongate the back of my neck.  I feel I have to seek out further advice.  Possibly from an Orthopedic surgeon.