Second molar extraction. Molar tooth?

Hello.I have got removed my lower wisdom tooth with general anesthesia as I am experienced lot of pain with local anesthesia. Now that wisdomtooths neighbor tooth is decayed and it got hole in its wall(second molar tooth).I am getting pain.Now dentist said to extract it as it is in bad condition.It is not in stage that dentist can do root canal.I became too much anxious. I have some psychological disorder like ocd.my question is 1.What I should request my dentist to decrease the pain while extraction? 2.what is sedation?How it given?what will be my feeling after getting sedation? 3.is it second molar tooth extraction is very painful? 4.how much time it will take to extract lower second molar tooth? 5.suggest me best toothpaste to get my strong gums and tissue.