In flight school we sat in a hypobaric chamber to simulate flying at 30k feet to induce hypoxia. When they would bring us back down, we would have to execute the valsalva maneuver every 1000–2000 feet. On descent, the pressure in the cabin increases, while the pressure in your middle ear stays roughly the same. This is what causes the pain or discomfort. Holding your nose and blowing (like you would do if you were diving), forces more air into your middle ear (via the Eustachian tube), and equalizes the pressure.
I still hate doing the Valsalva. It feels like I’m going to rupture my eardrums. But so long as you blow slowly and steadily, you won’t, and it will most likely help your problem.
Just remember though, only perform the Valsalva on the descent! Doing so on the climbout will cause you to rupture an eardrum. Chewing gum and/or yawning is the best way to let the pressure out of your middle ear when climbing.