Hi,

PICs which feature ADC have multiplexed inputs. That is either they go to the ADC or the digital I/O. By default (POR) the inputs are analogue. There are registers to set this according to your app. For your PIC it is the ADCON1

ADCON1 = %xxxx0110 ' where the x is your own setting turns of the ADC inputs and configures all as Digital I/O.

Read page 129-130 of your datasheet.