My head thumps like a ripe watermelon

From time to time, something happens somewhere from the neck up, which results in my head sounding like a ripe watermelon (from the inside) (although I’ve never been inside a ripe watermelon, so I’m extrapolating) when I comb my hair and thump my head with the comb, when I tap my head with my knuckles, even when I clamp my teeth together. Then it will just go away after a few days. Sometimes it’s just on one side- so I can tap my head on the right and it sounds perfectly normal, but on the left, it sounds like a ripe watermelon, but right now, it’s on both sides. I’m guessing this has something to do with my sinuses or my Eustachian tubes or something. It’s not painful, but it is annoying. When I talk, it sounds a little like I’m under water.

What is this? Can I make it go away faster?

My head’s not stuffy like with a cold or anything. My nose isn’t runny. I don’t have a headache. It doesn’t feel like it’s in the front of my head (face), but like it’s from my ears back, but all the way to the top of my head. Like my head is a balloon filled with water.
*ETA: Apologies to all who clicked into this thread expecting it to be about a new country song. *

Might need tubes in your ears. Ear Tube Placement

I cannot travel via airplane anymore. I need to do it for business travel. Pilots and flight attendants get it done. The procedure takes about 39 seconds.

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Interesting… I did get hearing aids a few months ago.