What Causes Swollen Shoulder, Hand And Collarbone After An Injury?

I injured my left shoulder a few months ago it was hard to lift my arm. I figured it would heal itself bit i still had slight discomfort. Now my shoulder has swollen and has spread to my collarbone and around my left shoulder blade it is tender to the touch. When I woke up this morning my right hand was also swollen but it went down what could be the cause of all the swelling?