buttons on pin 13 and 7 dont work

hello bit confused at why this does seem to be working. im using max to control the serial but the buttons on 13 and 7 dont seem to be working, any ideas why??

int ledPina = 11;
int ledPinb = 10;
int ledPinc = 9;
int ledPind = 6;
int op;

int vala;
int x;

void setup()
{
// begin the serial communication
Serial.begin(9600);

pinMode(ledPina, OUTPUT);
pinMode(ledPinb, OUTPUT);
pinMode(ledPinc, OUTPUT);
pinMode(ledPind, OUTPUT);
}

void loop()
{

if (Serial.available()) {

op = Serial.read();

if (op == 1) {
delay(5);

vala = Serial.read();
analogWrite(ledPina, vala);

}

if (op == 2) {
delay(5);

vala = Serial.read();
analogWrite(ledPinb, vala);

}

if (op == 3) {
delay(5);

vala = Serial.read();
analogWrite(ledPinc, vala);

}

if (op == 4) {
delay(5);

vala = Serial.read();
analogWrite(ledPind, vala);

}

if (op == 9) { // If an ‘4’ is received then read the pins

for (int pin= 0; pin<=5; pin++){ // Read and send analog pins 0-5
x = analogRead(pin);
sendValue (x);
}

for (int pin= 2; pin<=13; pin++){ // Read and send digital

if (pin == 6){ pin++; }
else if (pin == 9){ pin++; }
else if (pin == 10){ pin++; }
else if (pin == 11){ pin++; }

else {

x = digitalRead(pin);
sendValue (x);

}
}

Serial.println(); // Send a carriage returnt to mark end of pin data.
delay (5); // add a delay to prevent crashing/overloading of the serial port
// dealt with with the metro, kept here for reference

}

}

}
void sendValue (int x){ // function to send the pin value followed by a “space”.
Serial.print(x);
Serial.print(32, BYTE);
}

I'm just guessing here but it doesn't look like you declare either of those pins to be inputs.

yea, you definitly need that

in the code, add "pinMode(7, INPUT);"

same for the other pin

good luck!