Above posters covered pretty well what types of opiods there are for you to take.
I wouldn't worry to much about getting addicted to them (still be cautious). People who are opiate addicts process and break down the drug differently than normal people. We have a certain chemical change in our brain when opiates enter which produces a supreme euphoria unlike any other type of drug.
This doesn't occur in most people though, most do not receive any type of high at all. They just get pain relieved and sometimes throw-up because their stomach is un-easy.