Increased Muscle Tension
Anxiety's feelings of danger and dread trigger your fight or flight reaction, resulting in increased physical strain and tension. This can cause trembling in your hands or other body parts, as well as severe headaches and pains in your neck, shoulders, and back (where many people carry their tension).
It might be a symptom of an anxiety disorder if you tense up more the more nervous you are, or if you notice that you're unusually tense throughout the day without any clear or immediate reason (that is, you're in a permanent state of readiness). Relaxation techniques such as meditation or breathing exercises are one way to relieve muscle tension throughout the day. There are a number of mediation apps available to assist you with these practices.