I also have the same thing you have and the doc told me it was a cist ( fatty tumor ) I get those sharp pains and they will go away then come back also
I have not had mine taken out but thinking about it ! very serisusly
I had a lump removed from my back between my shoulder blade and spine. At first it didn't really bother me, but as it slowly got a little bigger, it seemed to be pushing on muscle or nerve and would cause discomfort sometimes. I had it checked out and it was a benign cist (or fatty tumor). Evidently, these are very common, especially in the back. I had it removed in the doctor's office, and they ran tests on it just to be sure. OK.
They said that sometimes they grow back.
I would suggest you get it checked out. It's probably no big deal, but better to find out now.
I personally say its a knotted mucle, i have tons in my back from years of martial arts pulling my mucles and from being a retard with friends...
But get it checked out just in case.
i don't know the size, but could it just a knotted muscle? is it sore? you should probably have it evaluated by a dr. just to be safe, tho.