Please, when you post a question, give us all details such as PIC #, Using internal OSC or not, String format or Bin or Dec format. Same thing on PC side, which software, setting etc etc.

First thing to try, send a text string to the PC, if everything is correct, send a text string + 1 byte of data from your PC to the PIC and use WAIT modifier + 1 variable. if the content of the variable match everything should be correct... at very least the hardware.