Kindly visit the dentist. Pain should not linger on unless it was  very difficult to remove the tooth.

you need to check it...because the muscle growth you are mentioning is nothing but the growth of gums and bone on the extraction site which is essential.. the pain should not be there after a month but if it's there kindly get it checked if it's a severe amount of pain... if it is moderate and bearable then you need not worry... but ultimately just a check up can save you from future uncalled ailments :)