What Causes Pain Below Scapula After An Injury?

A few weeks ago I was picked up in mid air and dropped to where my shoulder hit the floor hard and my head went back. I had a headache, but it wash t a concussion luckily. My left shoulder has been hurting ever since then, but it is a sharp pain. Every once in awhile the pain goes to my neck. It hurts above and below my scapula. The X-Rays didn t show anything, any clue what it could be?