Well, I wouldn't trust Ancestory.com as a good source for finding geographical or place names especially in languages like Finnish.
There is a pretty famous place called Pajala but it's in Sweden, way up north.
http://en.wikipedia.org/wiki/Pajala
This guy called Mikael Niemi wrote a book about that region and about the dialect people talk there. Don't ask me to translate the name of the book.
http://en.wikipedia.org/wiki/Mikael_Niemi
I'm guessing that could be where the last name Pajala may have originated from although it could be from elsewhere also. As HT above wrote it could come from some other source as well. Maybe do a blood test on your dad and determine the genetic background?
edit. Hahaa, my sig works.