What Causes Pain In Rib Cage While Suffering From Flu?

Hello, after having the flu and then a week later excessive coughing, I had a pain in the top of my rib cage (right side) (under my breast) that was sore like muscular pain. It went away after two days but still coughing. Suddenly I had pain on the left side which is not going away and which feels more and more sore. It even seems to by going around to my back. Could this just be sore from the coughing still?
Thank you in advance