Pain is usually due to infection around the mucosa of the erupting last teeth. Ultimate solution is to get rid of this tooth by minor surgery called as disimpaction.

It is unlikely for the wisdom tooth to erupt after 21 or 22 years of age. You feel it is erupting because of inflammation in and around the gums (which is called as pericoronitis) tends to show exacerbation and remission. There are very few cases in which any other treatment can be done but in maximum cases the only permanent solution is the extraction of the offending tooth which needs to be done as soon as possible before the symptoms aggravate further. An x-ray called as OPG will be required to evaluate the condition of the bone and the root before planning the extraction. Regards.