Ur question has plenty of probable reasons ,maybe because of incomplete biomechanical preparation ,presence of pulpal remnants ,presence of accesory canals ,overinstrumentation .. Take a ketrolDt incase the pain is excruciating .. But make sure u dnt have any intestinal problems .. Visit a different dentist and take there opinion

You should take medications for 2-3 days after root canal. Visit dentist to relieve pressure on the tooth. Post a after RCT x-ray.

As u mentioned permanent cement is it normal filling or root canal treatment? If it is normal filling and if u r having pain and if that pain persists means filling should be removed and if pain is only during eating and it is relieved once u stop eating means u can go for indirect pulp capping. If pain is not subsiding after stop eating then proceed with root canal treatment. If root canal treatment has already done means just wait for the painful state of tooth to become normal state which is normal for 3 days to 1 week after root canal treatment.

A mild pain after root canal treatment is very normal and common. Give it at least 10 days as after the treatment the area needs to heal. So wait for 10 days at least and let your dentist know about the same  No medicine is needed as far as it's not causing you severe discomfort in day to day routine  Don't start chewing immediately on that area wait for at least a week and then you can start chewing solid food from that area.

If root canal treatment is done it will take a week to settle down . And take your medicine too if there is pain. Else the filling can be little bit higher then normal set of occlusion reduction of feeling can be done . Before putting cap the pain should settle down else after putting cap the pain will continue . You can visit our clinic too if u r from mumbai.