Causes of neck spasm

• Anxiety
  Anxiety
  Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
  
  
• Muscle strain
• Tension
  Stress (biology)
  Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
  
  
• Tetanus
  Tetanus
  Tetanus is a medical condition characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by the Gram-positive, rod-shaped, obligate anaerobic bacterium Clostridium tetani...
  
  
• Spasmodic torticollis
  Spasmodic torticollis
  Spasmodic torticollis is a chronic neurological movement disorder causing the neck to involuntarily turn to the left, right, upwards, and/or downwards. The condition is also referred to as "cervical dystonia". Both agonist and antagonist muscle contract simultaneously during dystonic...
  
  
• Stress
• Viral infection
• Whiplash injury
  Whiplash (medicine)
  Whiplash is a non-medical term describing a range of injuries to the neck caused by or related to a sudden distortion of the neck associated with extension. The term "whiplash" is a colloquialism...
  
  
• or other causes of spasm
  Spasm
  In medicine a spasm is a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ, or a similarly sudden contraction of an orifice. It is sometimes accompanied by a sudden burst of pain, but is usually harmless and ceases after a few minutes...