Can't handle 2 photoresistor at the same time?

Projects Programming
1 
int photocellPinl = 5; 
int photocellPinr = 0;
int photocellright;

void setup(void) {
  // We'll send debugging information via the Serial monitor
  Serial.begin(9600);   
}
 
void loop(void) {
  photocellleft = analogRead(photocellPinl);  
    photocellright = analogRead(photocellPinr);  
 
  Serial.print("Left reading = ");
  Serial.print(photocellleft);     // the raw analog reading
 Serial.print("      Right reading = ");
  Serial.println(photocellright);     // the raw analog reading

 
  delay(100);
}

Why the right photoresistor keeps read 0 value while the left one is working properly? I try to swap the components and exchange the pin , either one photoresistor must read "0". If I unplug the "0" value analog pin, it reads something, but I plug the pin back it, it reads 0 again. So it occurred to me that the 2 photoresistors can not operate at the same time?

All one knows why?

2

So it occurred to me that the 2 photoresistors can not operate at the same time?

It might but you would be wrong there is no reason why two photo detectors can't be used at the same time.
Unless of course you have not wired them up correctly.
Photo cell from analogue input to ground, then 10K resistor from analogue input to +5V.
Is that how you have them?