Are pain relievers bad or the kidneys ?

If you take Tylenol in large amounts and take it daily, then yes. But as another answerer said, always drink plenty of fluids to flush the kidneys and help get rid of poisons and impurities. Acetominophen, when used as directed, is a great pain reliever and will not cause damage. Anything you overdo can hurt you. Even aspirin, which has been around for years can hurt if you overdo it.