Welcome to the forum.

When using the serial hardware ports an inverter chip or circuit is needed between the PIC and PC, (MAX232)..
PC hardware sends/receives inverted data
PIC hardware sends/receives true data

And the DEFINES for HSERIN/HSEROUT need set in your code.

You may want to use SERIN2 to get started. SREIN2 is a bit banging approach that can receive inverted data.