How painful are root cs?

I'm fifteen and have to get three root cs in less than a month (I'm not sure if it's all on the same day) <---this is because of trauma due to hitting concrete on my mouth while on a scooter. I've had many baby teeth previously pulled, so I'm more tolerable of the novocaine shots. But I've never had a root c, and am very scared of what to expect. Also this thursday I have to go in to get some type of medicine thing? I'm not sure what that's about either...so anyone, please help me, I'm very worried :[