Is tylenol (acetaminophen) #3 is better than percocet for my back pain?

Depends. Choice of pain meds in terms of efficaciousness as well as side effects is very much an individual thing i.E people react differently.
Better med. The answer whichever one works better would be the one to use as long as there are no side effects.
Percocet T3 (liothyronine) I think of Percocet as stronger than T3 (liothyronine) but better is individual the one that works best with fewest sideeffects is the onecfor youctry both at different times and pick your favorite good luck i often recommend Soma and ultram prior to narcotics.