Hello! Thank you for the query. When the chest pain appears some time after vomiting, pneumonia due to vomits aspiration should be ruled out. In such case, shortness of breath and cough should be also present. Other possible reason of your chest pain is stomach or esophagus irritation due to poisoning or vomiting. It could cause stomach or esophagus inflammation or aggravation of the persisting stomach disease like peptic ulcers. I suggest you to visit your doctor for physical examination (chest checkup). You should try mild diet for few days along with probiotic. Avoid fatty foods, spicy foods, alcohol and coffee. If the pain wont go away in few day, you should have gastroscopy done. Hope this will help. Regards.