What Causes Chest Pain During Exhalation While Suffering From Flu?

It does not hurt to inhale but to exhale is excruciating over my right chest. Have been sick with flu ish symptoms for a week now. I am dizzy and weak, horrible cough, head totally clogged. Severe head pressure. I thought it would go away but now my right chest hurts, but only exhaling? What is the reason for that?