Chest pain or dyspnea is a common complaint associated with spontaneous pneumomediastinum, but this presentation is often subtle or non-specific. Spontaneous pneumomediastinum presents as neck discomfort if associated with cervical subcutaneous emphysema. A 17-year-old male adolescent was bothered by lower cervical tightness and pain when exercising. A local myofascial sporting injury was impressed at the primary clinic. However, two hours later, a sore throat compelled him to visit our emergency room. A physical examination of the head, neck and chest did not show any abnormality. A blood examination showed leukocytosis. At this point an acute upper respiratory infection or acute epiglottitis was impressed. Follow up neck radiography, chest radiography and chest computed tomography demonstrated pneumomediastinum with cervical subcutaneous emphysema. He was admitted to hospital and treated conservatively over the following two days. Based on the above, a primary clinical physician should be aware of the possibility of spontaneous pneumomediastinum if they encounter a young man who has post-exercise cervical discomfort even in the absence of chest pain or dyspnea. Most spontaneous pneumomediastinum is benign and self-limited. The prognosis is good and recurrence is rare. However, the disease may involve spontaneous esophageal rupture (Boerhaave's syndrome) and may be complicated by airway obstruction, pneumothorax, tension pneumomediastinum or pseudo-cardiac tamponade.