Don't wait for pain med the surgi-center gave you to dissipate all of the way. If you feel discomfort at the site of your surgery, take the medication. You'll have to keep it at a certain level in your system for a while.
No sense letting the medication completely dissipate frrom your system causing you to be in pain while waiting for the medication to build up it's level again. KEEP THE ARM ELEVATED.
I'm only a few minutes away, let me know if you need something.