This has been a long term problem for me, but in the last couple of months the pain between shoulder blades has gotten much chronic and severe. At first it was only occasional and I was able to deal with by taking a couple of Tylenol 2′s. Now it is almost every day and it can come from nowhere. I can be doing something mundane when it flares up suddenly and with great pain. It seems to me that it might be some sort of nerve problem, like a pinched nerve. I think that because it seems like make a sudden or particular type of turn will cause the flare ups. For instance if I am driving it often happens when there is a need to look back over my shoulder.