Hi, thanks for your question. Please rate my answer if you are satisfied. There is a small tube called the Eustachian tube that connects the middle ears with the upper part of throat near the nasal opening. It maintains the air pressure on both sides of the ear drums. Eustachian tube gets blocked usually when you have a congested nose or a throat infection. This causes a pressure difference around the two sides of the ear drum and the ear drum may pop out or may be drawn inwards. This may cause abnormal popping sounds that your son is hearing. This is not a dangerous condition as it should go ,within a week, most likely as soon as your son doesn t have a congested nose/infected throat and the Eustachian tube is no longer blocked. Your son might need a nasal decongestant spray to get it better. But if your son has a long standing nasal congestion problem due to some allergies for instance, the Eustachian tube dysfunction for longer periods can cause accumulation of fluid in the middle ear cavity and that might need a small surgical intervention to deal with. Feel free to contact me. Regards.