I have what feels like a knotted muscle in my right shoulder blade, between the shoulder blade and my spine, I am now experiencing what feels like a vice squeezing the front of my chest and the sore spot in my back, it is a tingling and tightening sensation, when it appears in the front it also happens in my back, the pain in my back is almost unbearable. I do have heart disease and I had my heart checked out last week, and this pain is not related to my heart. the pain goes up the back of my neck and it hurts to lower my chin to my chest. is this like just a sore muscle or could it be something more serious.