What are some other contributing factors that make a change in pressure hurt your ears so badly?

I had a really hard time wording that question… hopefully it makes sense

I’ll never forget a flight I took from NY to CA a little over a year ago… when we started to descend, the pressure change caused such massive pain in my head and ears that I was hysterically crying. I know this happens to little kids but as an adult, I was very confused.

On a flight earlier today, I began to feel sharp pains again (but haven’t on any other recent flights) and they stopped. I know chewing gum and yawning help relieve the pain but sometimes it just doesn’t work. I have also noticed that driving in the mountains messes with me for some reason. What gives?

So I want to know, why is it that this happens? Is there a reason why it’s worse sometimes for certain people, and young kids? I was wondering if my allergies and resulting congestion contributed to the pain being so bad. What kind of preventative actions can be taken in advance?

Thanks!