Back to flaming back

My back is killing me at the moment, I have this knot right in the upper middle section of my back (around the middle of the lower shoulderblades), that is starting to get unbareable. I have never been one to have sore backs or anything (the occasional cramped neck or shoulder from sleeping on it funny, but that is it), thus this annoying pain (not really hurtful, more fraustrating) is really getting to me.