You could use three pins which you power up together, or that 2N2222 needs to be part of the ground return leg of your module. In other words, connect the Emitter to ground, Base to the PIC pin through a 4.7 K resistor, and the Collector to the ground side of your module. If I were to do it this way, I would put a bypass capacitor of .01 uF across the Emitter and Collector leads. To control the positive rail, the 2222 would be attached to the Base of a 3906 through a 2.2K resistor. The 3906 Base is also connected to it's Emitter through a 10 K resistor. The Emitter of the 3906 goes to the positive rail, and the positive side of the module connects to the 3906 collector. A high on the pin would turn the module on.

Ron