My right hand and arm for the past several years has been turning purple/bluish on random occasions. At my desk working with a mouse, or trying to stand up straight for posture putting shoulders back. It feels as if someone has tied a rubber band at my elbow and I am just waiting for my arm to explode. I have to eventually try moving my fingers and arm around in order for it to go away. Any ideas on what this could be? Also I have noticed lately that my right shoulder droops more then my left!!