There's just not enough time in the day to get everything done, and not enough time at night to rest and unwind. When you feel stressed, your body reacts and becomes tense. Dealing with stress is a daily challenge. You're doing a great job of recognizing signs of stress, so now you can concentrate on managing it.
Different techniques work for different people.
Set aside time for yourself. Find a quiet place away from distractions like telephones and televisions. Sit in a comfy chair with your feet on the floor and your arms relaxed at your side. Close your eyes. Imagine, in as much vivid detail as possible, how it looks, smells, sounds, and feels.