Have you ever closed the lid on an air-tight container containing a left-over hot meal and stuck it in the refrigerator? And than when you try to open the lid the next day once that hot meal cools down, it is REALLY hard to open the lid because of the accumulated negative pressure? In essence, the negative pressure has "locked" the lid down.Well, something similar can also potentially happen inside the ear with eustachian tube dysfunction, especially with negative pressure (rather than positive pressure).
Eustachian tube dysfunction is a phenomenon whereby a person is unable to pop their ears to relieve symptoms of ear pressure, clogging, or fullness. It is much akin to the ear pressure a person experiences when flying, but at ground level. Traditionally, treatment of this condition involved medications like steroid nasal sprays and prednisone along with active valsalva (watch video below). Once medical treatment has failed, ear tube placement has been the step of last resort.
The question some patients have is WHY does it become so hard to get an ear to pop open with eustachian tube dysfunction...
It may be that the mucosal lining of the eustachian tube has swelled to the point that there is no opening present.
There may also be a physical obstruction blocking the eustachian tube due to large adenoids, nasal polyps, or some other nasal mass.
However, a lesser known phenomenon is due to the negative pressure itself creating a suction effect on the lining of the eustachian tube analagous to the stuck container lid mentioned in the first paragraph. The middle ear negative pressure itself may be literally "sucking" the lining of the eustachian tube closed. If the negative pressure is great enough, it may be very hard to get it open.
When this happens, the eustachian tube becomes "locked".
One can "mimic" this effect even in a healthy individual (not that anybody would want to try). When a swimmer dives deep into the water, some ear pain will start to develop due to the negative pressure building up in the middle ear. If the swimmer does not ear pop and continues to go deeper into the water, at around 3.9 feet, it may start to get very difficult to get the ear to pop open even with effort. At around 5 feet of water depth, it will become impossible to pop the ear open. Normally, swimmers and SCUBA divers continuously ear pop when diving at depth to prevent any ear discomfort.
As such, in situations where negative ear pressure is present and medications fail to resolve the ear clogging, a hole can be surgically made in the eardrum WITHOUT tube placement which will often resolve the symptoms fairly quickly. The hole "releases" the negative pressure to allow the eustachian tube to function normally. The analogy would be that once you release the negative pressure within an air-tight container, it becomes very easy to remove the lid thereafter.
The eardrum hole typically heals closed in a few weeks and the clogged ear sensation will often not come back. If it does, the myringotomy (surgically creating a eardrum hole) can be repeated and if necessary, a tube can be placed to prevent the body from healing the hole closed anytime soon.
Some things that have helped some people to pop their ears:
for 
for you to "experiment" with.
to be used 30-60 minutes before ascent and descent.
