What is pale pilsen? We have this local beer in the Philippines called San Miguel Pale Pilsen. Looking at this style guide I don't see any mention of the word Pilsen, though there is the word Pilsner. Are they in any way related?
Yes, they are related. The pilsner beer style got its name from the city of Pilsen, in what is now the Czech Republic, where the beer was first brewed in 1842.

Reference: Pilsner