Hi! Welcome to Healthcaremagic. I read your query. Please check if any of his teeth have caries or there is pus or plaque anywhere in gums.If so, it needs to be treated by a dentist. Also, as you mentioned he has cold, ear infection and swollen gland. This infection can be the reason for this pain and discomfort. Also at times medicines (he might be taking for infection) can cause side effect like this. I suggest you to first cure his existing infection completely with proper antibiotics suggested by his pediatrics. Maintain proper oral hygiene. Brushing twice daily, rinsing after eating anything. Syrup ibuprofen can be given for pain. Give healthy diet. Ask physician for multivitamin supplement. If symptoms persists or worsen, show a dentist for further investigation. Hope the answer helps you. Thank you!