A 30-year-old man presents to the Emergency Department with acute shortness of breath and left-sided pleuritic chest pain that started suddenly 2 hours ago. He is tall and thin and has no other medical history. On examination, his respiratory rate is 24/min, oxygen saturation is 95% on room air. Percussion note is hyperresonant on the left side, and breath sounds are diminished on the left. What is the most likely diagnosis?