My Tonsils Are Swollen. However Only My Left One Hurts.

My tonsils are swollen. However only my left one hurts. My tonsil hurts to swallow, talk, and move my head. Other than my left tonsil being in pain I feel fine. No fever, aches, etc. Also was tested for strep and results came back negative. One more thing to add is that at night and in the morning is when my left tonsil is in the most pain. What could I have? How long til the pain will go away?