This is not reading the position of the switch, you need something like:
if (digitalRead(switchA) == HIGH)
similarly:
else if(switchA == LOW)
Needs changing in a similar manner.
Here you are checking whether "switchA" is equal to zero (which is what LOW means), but it can never be, because it is a pin number (which you have set to be 6):
int switchA = 6;