I got a bow and arrow and used it for about half an hour and now i have pain around my left shoulder blade. i get a sharp pain doing certain things.

The "shoulder blade": or scapula is an integral part of the shoulder and responsible for a significant amount of the shoulders range of motion. The shoulder socket is a part of the scapula which also houses the rotator cuff muscles, an external and internal rotator muscles. If you have not used a bow before it is likely you either have a rhomboid or levator scapula strain both of which are common and short lived.