Max Pain keeps changing and is not a fix type of indicator till very near end of expiry of the contract as knowing max pain at the beginning of the month wud just keep ur mindset in a prejudice and may mislead you in the trade.
Instead I suggest you to follow a more reliable indicator possibly leading one like supertrend or RSI etc. coupled with PCR to give u an edge in making trading decision eg. PCR > 1, RSI at 20 in hourly timeframe… think what you need to do… ? buy of course… max pain will just confuse u more (As it used to do me as well 
) All the best