You need an embassy visa for South Korea if you have a Pakistani passport
Visa options for South Korea
Visitor visa
Travellers need a visa to visit South Korea for Business or Tourism. A paper or embassy visa is the only visa available for travellers visiting South Korea. The visa is typically a stamp or sticker added to the passport. Travellers must obtain this visa from a local embassy, consulate or visa center before travelling.
This is not offered by sherpa°.
Apply on the government site.