For the last week, I have had a burning, stabbing pain in my left shoulder blade/back area. The only relief is when laying down, using a heating pad. It is mostly constant though there are some greater spasms and times of relief. It is also accompanied by some numbness/poor circulation in fingers and toes. I don't have health insurance and don't know if this warrants a trip to the ER. Is it just a pulled muscle? Or something more serious?