As BubbleTrubble articulately put it, this is almost certainly middle ear barotrauma. I wrote a little ESSAY about ear infections, to try to give people a little better sense of what's outer ear and what's middle ear, and what drops or rinses will help with and what they won't.
Just wanted to point out that it's NEVER spinal fluid, and rarely blood; it's usually just edema fluid from the tissues surrounding the air space in the middle ear. If the squeeze is severe, capillaries CAN rupture and you can get some blood in the fluid. You will never get spinal fluid in your ear, absent a basilar skull fracture.
an inability to equalise causes blood and spinal fluid to be forced into the middle ear which leaves you feeling as if you have water stuck in your ear, and your hearing is a little muffled.
Just wanted to point out that it's NEVER spinal fluid, and rarely blood; it's usually just edema fluid from the tissues surrounding the air space in the middle ear. If the squeeze is severe, capillaries CAN rupture and you can get some blood in the fluid. You will never get spinal fluid in your ear, absent a basilar skull fracture.