United, I had the same sensations and I thought of the worst because of heart disease in my family. My girlfriend helped to point out that I had been doing a lot of pushups, which might involve a similar stress to the upper body that you would get from moving furniture. i identified that the shortness of breath and soreness felt like it was in the muscle and not internal and was irritated when I breathed heavily or coughed (like from smoking). I'm no longer worried . I hope your story ends as simply.