What is causing this extremely sore throat?

A couple of months ago, I got the worst sore throat of my life. It was excruciating. It felt as if the skin in my throat was being ripped apart. It was way in the back too, more like the inside of my neck. I couldn't even move because that would cause me to cough, which would set my throat on fire. I had a fever as well. This lasted for about a week, and then I got better. Since then, I've had 'flashes' I guess you'd call it. They're like much more mild versions of it. I can't figure out what's wrong though. I went to the doctor, and all he said was that it wasn't strep. I was briefly worried that I could have throat cancer, but since I'm a teen, that's pretty unlikely.