pain under collarbone

hello  last few weeks Ive been experiencing pain under my right collar bone or around it , I cant seem to localize it. I dont know where exactly the pain comes from.  but it only hurst when I put my right hand behind back and push my right shoulder forward etc. I dont feel the pain when im moving my hand normally. (sorry if my explanation is bad) Do anyone know what can be the cause of this ? or has anyone experienced it too ? thanks