Grinding or clenching your teeth, especially at night, is very harmful to many oral structures. This can cause jaw joint problems, headaches, neck aches, facial pain and, most commonly, fracturing of teeth, creating a need for extensive restorative dentistry.
Stress in any form usually makes the grinding and clenching worse. Relaxation techniques and a night guard will help break the pain/damage cycle. There are two options for relief: many different over-the-counter night guards and professional lab made appliances that will help the severe grinders.
Always consult your dental professional with pain or questions related to night guards.