I m having these deep, somewhat sharp pains on the left side that feel like they re deep behind my clavicle maybe three inches from midline. It s been hurting for a few months on and off and is exacerbated by exercise involving the chest muscles and deltoids, as well as raising my arms overhead. I also feel a clicking when doing exercise like a chest press of flyers (like bones are clicking against each other). The pain feels pretty specific to this area, but also feels like my neck and shoulder are involved. Many mornings I have awakened with stiffness in that shoulder and neck as well as an large increase in pain; some mornings I have awakened with numbers in my left hand that feels less like a nerve impingement and more like a blood vessel blockage (when I reposition and go through ROM movements, it actually feels like blood is returning to my arm and hand). Do you have any ideas what it could be?