Final answer:
A patient with blunt trauma who is holding the lateral side of his chest and has rapid and shallow respiration's is most likely suffering from pneumothorax.
Step-by-step explanation:
A patient with blunt trauma who is holding the lateral side of his chest and has rapid and shallow respiration's is most likely suffering from pneumothorax. Pneumothorax is a condition in which air leaks into the space between the lungs and the chest wall, resulting in a collapsed lung. This can be caused by blunt trauma or other factors that cause a rupture in the lung tissue. The symptoms mentioned in the question are indicative of a pneumothorax, as the patient is experiencing chest pain and difficulty breathing.