No pain prior to having anterior appliance

thank you very much for replying.my family dentist told me i was grinding at night. i had no pain or obvious problems, so i told him to forget it, but he kept insisting. he made me a night guard which looked like a retainer i wore in 7th grade after i had braces. he instructed me to wear it at night, and if i was stressed to wear it during the day.i wore it from march of 08 and my pain started in