However, just as the cough started to subside, I began experiencing a sharp stabbing pain around my lower right rib cage whenever I coughed. This pain increased over time and it became painful to move that area of my body.

After a bit of research (mainly here) I discovered that I had pulled an Intercostal muscle.

I bought some cough syrup, which did ease my coughing a bit. Fortunately the cough subsided just as the pain was getting quite bad. I also found that pressing my hand up against the sore spot as I coughed would lessen the pain a little.

It took about two or three weeks for the muscle strain to go away completely. It really mucked up my running schedule because I stopped when the cough started and, because of the subsequent muscle strain, couldn’t start again for over a month!

In retrospect I should have bought the cough syrup earlier, as reducing the amount of coughing even by a little bit could have helped me avoid the muscle strain entirely.