Hello and Welcome to HCM,
Thanks for writing to us.
The most common cause of pain from impacted tooth
is the inflammation in the soft tissue
covering over the offending tooth(Pericoronitis
), mostly caused by food impaction
in the soft tissue space over the tooth and/or bite injury
over the soft tissue covering the impacted tooth, by upper molar tooth.
As your third molar has remote possibility to be erupted in the mouth(as cover by bone and no space to be be erupted) the symptom like pain may frequently appear. The Third molar has no function for mastication(chewing) or maintaining occlusion, so it is always better to extract the tooth when it starts causing problem.
In an experienced surgeons hand your impacted tooth can easily be extracted without causing much problem.
Hope this helps you.
Wishing you good health...