Did Google give you a date that you should expect to receive the PIN by? If so and this date has been passed by more than a week, I would certainly contact Google and request that is it resent. (Another long wait then though)
Is the account operating acceptably apart from not receiving a PIN? Have you earned $100 yet? If you haven't earned $100 before the end of January you will not be due a payment before the end of February anyway.