Really sharp pain around shoulder blade. it hurts to move my arm what could it be ?

Muscle spasm: Sounds like a common problem people get due to spams of a group of muscles under and around the scapula (shoulder blade). It is painful and distressing. Usually self limited and treated with heat or ice, massage and Ibuprofen type meds. May need some physical therapy and or muscle relaxers if doesn't go away. If in doubt get in to pcp and be seen.