There are white items attached to my tonsils. What are they? What caused them? How do I treat them?

TONSILLITHS. Most likely these are debris caught in tonsillar crypts. They would be benign but you should see ENT doctor for validation.
Could be many things. Those "white items" could be from inflammation caused by smoking, acid reflux, snoring, or viral infections like colds. In most cases, uvulitis will subside in 24 to 48 hours, you can gargle with warm salt water and try abstaining from the causative factors is smoking etc...
Tonsilliths. They are bacterial colonies that builds up in the crypts of your tonsils. See an ENT doctor for exam. And treatment options.
Tonsillar stones. The. White items represent debris caught in the crypts of the tonsils. They harden into "stones" and are benign.