Hi, thanks for your question. Headache and vomiting might range from a mild primary headache (migraine, tension headache or cluster headache) to secondary causes like infections, trauma and other causes of intracranial hypertension). It would be interested to know if he has fever or not. Association with chest tightness is worth investigating, especially if he had never experienced it before. Association with other respiratory symptoms like wheezing or cough at night could suggest asthma. A family history of asthma too could help. It is imperative for him to carry out first a chest X ray to rule out a pneumonia, suggestive signs of asthma or may be a pleural effusion. Complete blood count, ESR, CRP will be important in evaluating an infectious origin, an increase in level of eosinophils might suggest an allergic reaction, confirming may be an allergic cause. I suggest you visit an internist for a proper evaluation. Thanks an hope this helps, Best regards, Luchuo, MD.