Final answer:
The next step would be to obtain a chest X-ray to evaluate for a possible tension pneumothorax.
Step-by-step explanation:
The next step for a 42-year-old man who was in a motor vehicle crash and presents with hypotension, distended neck veins, and normal breath sounds is to perform a focused assessment of the cardiovascular system. This includes evaluating heart rate, blood pressure, and filling pressures. In this case, the patient's symptoms suggest a possible tension pneumothorax, which can result in hypotension and distended neck veins. Therefore, obtaining a chest X-ray to evaluate for this condition would be the next step.