Hello... I Am Having Sharp Pain And Stinging, Even When

Hello... I am having sharp pain and stinging, even when not moving, on my mid-back next to my shoulder blade. This has been going on for three days now. I do get some relief with Anacin, ice pack, and heat and lying down. However, as soon as I'm off the heat and/or cold, it continues again. I don't recall twisting or pulling a muscle, but may have. It doesn't feel like a pulled muscle, however. What are your thoughts?