qhb
I would actually recommend you get the serial receive working WITHOUT interrupts first.
Just looking at what you have done, you have not shown any code which sets the RCIE bit, so you won't be getting interrupts when you receive anyway.
Are you switching the RX pin from analog to digital mode anywhere in your code?
In your ISR, you try to clear the RCIF flag. That flag is read-only, you CANNOT clear it like that. The only way to clear it is by reading RCREG.
 

void enable_interrupt()
{
 
 GIE=1; //Enable Global Interrupt
 PEIE=1; //Enable the Peripheral Interrupt
 TMR1IE=1; //Enable timer interrupt bit in PIE1 register
 TMR2IE=1; 
// PIE3 = (1 << _PIE3_RCIE_POSN); 
 RCIE = 1;
// TXIE=1;
 
}

void config_pin()
{
 DISABLE_ANSEL_PORTB;
 DISABLE_ANSEL_PORTC;
 DISABLE_ANSEL_PORTA4;
ANSE1 = 0;
 TRISE1 = 0;
 
 TRISB = ((1 << _TRISB_TRISB7_POSN) | (1 << _TRISB_TRISB6_POSN)|
 (1 << _TRISB_TRISB4_POSN) | (1 << _TRISB_TRISB3_POSN) |
 (1 << _TRISB_TRISB2_POSN) | (1 << _TRISB_TRISB1_POSN) |
 (1 << _TRISB_TRISB0_POSN));
 
 TRISC = ((1 << _TRISC_TRISC7_POSN) | (1 << _TRISC_TRISC5_POSN) | 
 (1 << _TRISC_TRISC2_POSN)|(1 << _TRISC_TRISC1_POSN) | 
 (1 << _TRISC_TRISC0_POSN));
 
 TRISA4 = 0; // PIN OUTPUT SHUTDOWN
 TRISD3 = 0; // PIN OUTPUT BACKLIGHT
 INACTIVE_BACKLIGHT;
 
 remap_usart_pin();
 PORTB = 0x00; 
 PORTC = 0x40; 
 
 // PORTE = 0x00;
 
}