Hello sir It's the pain of erupting molar You can do warm salt rinses and ideal treatment is get it removed

From the picture that you’ve shared, your second molar also does seem erupted properly meaning its still somewhat enclosed in your gums. A clearer picture could be more helpful firstly and secondly if its due to your Second molar, there are several treatments available which could help resolve the issue permanently. To know more about it, you can get a consultancy done.

Hello dear Please be advised Yes there can be pain post operatively after extraction.but after 3 months it is abnormal.i suggest you to please get clinical check up done for confirmation of diagnosis.for further details you can consult me Thanks