By American and British standards, nightlife in Campania's provincial towns tends to be dull. There isn't a bar culture in southern Italy, and often what's called a pub here is a rather pale imitation. Cultural and social life, though, are always lively, from strolling to and fro along the main street, to going out for dinner, to having an aperitivo, to eating handmade gelato ice cream, to going to the theater or to a movie.
Clubs can be found, but you may not want to go out of your way to be seen there. While there are some great clubs in Naples, the situation is quite different in the rest of the region. You'll find some good ones along the Amalfi Coast in summer, but in the interior you are in a very different atmosphere -- it isn't at all unusual for young people to drive all the way to Naples for a good evening out. Your best option will often be a concert. Musical events (both classical and pop, though the pop is in Italian) are sometimes staged in even the most remote little towns and villages.