An alert and oriented young male fell 5 feet from a stage, impacting a metal railing with the right side of his chest, just under his armpit. The primary assessment is negative for life threats, although he does complain of very painful breathing and has remarkable tenderness and crepitus over the fifth rib laterally in this area. Throughout care, which action is essential to perform?

A) Apply ice to area
B) Administer aspirin for pain
C) Monitor breath sounds
D) Splint site with a bulky dressing

C) Monitor breath sounds