Root Canals have a bad reputation as being painful procedures. A lot of this reputation comes from a time when we didn't have reliable anesthetics. We now have wonderful anesthetics that can keep you from feeling any pain during the procedure, typically resulting in a pain free root canal with just mild soreness once the anesthetic wears off.
It is also preferable to keep your tooth whenever possible rather than taking it out. Teeth serve an important job in helping us to eat, chew, talk and smile. If we lose a tooth, it can inhibit our ability to eat our favorite foods. Damage to the surrounding teeth and future tooth loss are also possible complications from losing a tooth.