1) An infection in the tooth's pulp can be painful, but if the pain goes away it does not necessarily mean the infection is healed as the pulp (nerves and blood vessels) can die, causing the pain to subside while other worse symptoms occur. 2) A root canal, if done correctly, should be painless as the procedure is designed to eliminate pain rather than cause it. 3) After a root canal, the tooth must still be treated with care through proper brushing and flossing as it remains susceptible to cavities and gum disease like other teeth.