I have severe pain under my left shoulder blade that started after I experienced excessive coughing, and it has gotten progressively worse. It hurts when I move or twist or when I inhale deeply. Sometimes the pain will shoot down my left arm, but it is not constant. What could it be?
You should consider following up with your physician. Pain like this could be due to pneumonia or you could've pulled one of the small muscles between your ribs. It's also possible to crack a rib after excessive coughing.
Here's some information that you might find helpful in the meantime:
Why Yoga May Soothe May Types of Chronic Pain
Music Therapy Can Relieve Pain