Some possible reasons for plugged ears include fluid, altitude changes, excessive ear wax or a foreign object, according to About.com. The treatment for plugged ears depends on the cause, and some treatments do not require professional medical assistance.
Fluid in the ears is one cause of plugged ears, and is usually due to a cold or allergies, explains About.com. In most cases, the fluid stays in the auditory tube instead of flowing through, which means it is stuck in the middle ear. Typically, this clogging goes away on its own, but if it is chronic, a doctor may prescribe tubes in the ears. A change in altitude, such as when flying, may also cause clogging in the ears. This, too, normally goes away on its own, but if it doesn't, it is important to see a doctor.
Sometimes, excessive ear wax causes clogging in the ears, but it is not common, because the ears naturally clean themselves out, states About.com. It is important that people do not remove excessive ear wax at home, as it can push the wax deeper into the ear. A doctor has special equipment to pull out the wax without rupturing the ear drum. If a foreign object is in the ear, it is also important for an individual to see a doctor instead of attempting to remove it at home.