4 Days Ago I Went To The Doctor With A

4 days ago I went to the doctor with a terrible cold and they told me it was bronchitis. Since then, i haven't gotten any better with the antibiotics they gave me. In the last couple of days my right shoulder blade/rib cage has been hurting really bad. I even went and got a sling for it today. It just keeps getting worse and worse! It's to the point I can barely breathe or move my arm without severe pain. The doctor that I went to today told me he didn't think I cracked a rib. What could this be?