Do I need to initialize my port pin?

Yes, you have to initialize your port pin by using BitIOLdd3_Init() function, which is part of the BitIO component for the push button:

Figure 1. BitIOLdd Component

You need to initialize it before main() function gets called, very early in the startup() code.

Note: When creating a BitIO component for Kinetis, Processor Expert automatically creates a BitIO_LDD component for it.