Some people grind their teeth only during sleep, while others grind during the day. Most often this occurs during situations that make them feel tense or anxious. But it can also come about from teeth not coming together properly, complications from head trauma or from psychiatric medications.
When severe bruxism (grinding) is present, it can fracture dental fillings, fracture teeth, cause chronic facial/jaw/joint pain or headaches. You may not even be aware that you are doing it but experience the symptoms.
If you exhibit any of these symptoms, make an appointment with your dentist for an examination of your teeth and your jaw muscles.