Next step after job offer

Last Friday, I had my first rn interview . It was residency program that starts on 9/29. I got a call from recruiter that day that I got the position. Today, after three days (excluding weekends) I haven't got any call from hospital. I called the recruiter and left a voice message but haven't got a call back yet. Is this normal? How long does background check usually take? I'm just waiting and don't know what the next step is...
The amount of time required for a background check can vary - depending on who is doing it. Most organizations out-source this function. If the company they use is very good, they can turn it around fairly quickly (~3 days). But it is not unusual for this process to take a week or so. Don't feel bad about following up and asking for a status report. You need to be informed so that you can make your own plans. Congratulations on the job offer!!
Congrats on your offer! I accepted a job offer in mid August for a new grad program that started in September and didn't hear back from HR until 1 week later but I kept following up as you did. Ever place does things differently tho