Just had the surgery today. My second one. The first, I screamed for two solid hours (I'm a 40 some year old man with a relatively high pain tolerance I thought) and refused to go back there for the follow up appointments for the crown. The second one (today, was about 45 minutes and relatively painless. It depends on the tooth and the dentist. With the abscess, that needs to get fixed before your root canal. Try the surgery with it, and not only will it hurt like hell, you'll be open to all kinds of infection. Good luck.