I move my jaw side to side, also unknowingly tighten my jaw. and sometimes when i wake up my teeth will be be clenched. what's the cause?

TMJ/TMD: Stress and malocclusion are two common contributing factors to TMJ/TMD. See a dentist who has experience and training treating patients with Temporomandibular Joint Dysfunction for a thorough evaluation and treatment options. Try to reduce stress in your life.

Possibilities: Malocclusion, parafunctional habits, neuromuscular disorder, skeletal malrelationship, etc. please see your Dentist. Referral to Orthodontist, Oral Surgeon, ENT, Neurologist, or Dentist who has expertise in treating Temporo-mandibular Joint Dysfunction. But start with a trip to your Dentist.