On Friday while i was at work i got a sharp pain in my upper back on the left hand side, like a sharp stabbing pain it has now left me with this pain but mainly when i twist or bend not when i am still, what could it be? it just suddenly came on. I happen to be going to see my GP on Monday about something else so i will mention it if it hasn't gone by then, am just not sure if it is muscular or something inside. Any ideas anyone?