Popping of the ears occurs when pressure or fluid inside the ear builds up and then suddenly escapes through the eustachian tubes, which are small tubes that run from the middle ear to the throat. The normal function of the eustachian tube is to equalize this fluid or pressure and prevent 'popping.' However, in some people the eustachian tubes are narrowed or swollen, preventing easy equalization between the middle ear and the throat. This 'eustachian tube dysfunction' most commonly occurs because of colds, throat infections, and nasal or sinus allergies.
Generally speaking, having your ears occasionally pop is not a major problem and will not cause any long term problems. However, you should avoid actively trying to pop your ears by pinching your nose or 'blowing open' your ears, as this may actually drive fluid up into the ears through the eustachian tubes and make things worse. Yawning, chewing gum, and gargling with warm salt water are all safe ways to 'pop' the ears.
If this problem continues or gets worse, you should talk to your primary care doctor
about a referral to an ENT (ears, nose, throat) doctor for evaluation and treatment of chronic eustachian tube dysfunction.