I have a sharp shooting pain in the top/middle of my back on the left hand side. i have had it for about a week, is it anything serious?

Probably not: Pretty vague symptoms - difficult to know for sure what is wrong. Minor things like an inflamed muscle or joint can cause temporary sharp pain. Given your reported age and assuming no other symptoms, this may resolve on its own or maybe with anti-inflammatory meds. If it doesn't go away, see your doctor who can do a thorough history & physical and make sure it's nothing serious. Good luck!