What's wrong with my tooth?

I remember back around a year ago, I had the biggest toothache of my life. It hurt so, so bad that I was taken to the dentist immediately and treated.

The toothache was a throbbing kind, where there was a throbbing pain on the tooth that occurred spontaneously, each more painful than the last (in my experience). I remember in the first few hours it didn't hurt that bad, it was just an occasional throb, but then it started getting more repetitive and worse, until it was unbearable. It was at the lower right back tooth, not sure if its my wisdom teeth or not. But it hurt like hell.

Now, a year later and after getting it crowned, its starting to act up again. It doesn't hurt as bad, but I remember it was like the beginning stages of the last, and I'm really dreading it. Like I'm really, really scared. What's wrong with my tooth? Is there anything I can do to get rid of it while its pain is still little before I go to the dentist?

Please help, and thanks for reading this.

Oh, and also if it helps I'm a sixteen year old girl.