What does it mean when your tonsils are swollen?

My left tonsil (sorry if I spelled wrong) seems to be bigger than my right. Ive had a very high fever for the past two days and just started to wear off today. I had the chills really bad but today I only had one flare up and it wasn’t as bad as past days. When I swallow it hurts a bit on the left side of my throat but I dont have any trouble swallowing. What does this mean? Do I need them removed?