Sunday Morning, I Woke Up With A Sharp Pain Beneath

Sunday morning, I woke up with a sharp pain beneath my lower right shoulder blade. The pain had continued up my right shoulder, making that whole area sore. If I try to breathe in as far as I can, I get a sharp pain from that lower shoulder blade area, and if I cough, that lower shoulder blade area gives me a sharp pain. Tylenol helps with the pain and I am taking the recommended dosage. I've never pulled a back muscle before and don't know if this is what it is. Your opinion?