One of my tonsils is very swollen, but the other is normal. It hurts really bad to swallow or talk. They aren't red. No other symptoms whatsoever.

Painful yonsil. Get help. You may have a tonsillar abscess.Upper air way x-rays are in order and an immediate evaluation by an ENT physician is in order.
Tonsillitis. Tough to say because lacking detail of duration of symptoms. Suspect this is a viral tonsillopharyngitis affecting one tonsil more than the other . Other symptoms may soon develop. Good supportive care with warm salt water gargles, tylenol (acetaminophen) or ibuprofen, and throat lozenges is good place to start. If symptoms last > 7-10 days, consider bacterial infection and see doctor for exam & culture.