The Efficacy and Safety of Trapezius MSAT on Acute Whiplash Injury

Inclusion Criteria: * Patients who needs hospitalization due to acute whiplash injury that occurred within 7 days after traffic accident * Patients with NRS ≥ 5 for posterior neck pain * Patients aged 19-70 years on the date they sign the consent form * Patients who provide consent to participate in the trial and return the informed consent form Exclusion Criteria: * Patients with a specific serious disease that may cause spinal pain: malignancy, spondylitis, inflammatory spondylitis, etc. * Patients with progressive neurological deficits or with severe neurological symptoms * Patients who have had surgery or procedures within the last three weeks * The cause of pain is due to soft tissue disease, not the spine: tumors, fibromyalgia, rheumatoid arthritis, gout, etc. * Patients with other chronic conditions that may interfere with the interpretation of the therapeutic effects or results: cardiovascular disease, kidney disease, diabetic neuropathy, dementia, epilepsy, etc. * Patients who are taking steroids, immunosuppressants, mental illness drugs, or other drugs that may affect the results of the study * If acupuncture is inadequate or unsafe: patients with hemorrhagic, receiving anticoagulants, severe diabetes and cardiovascular disease * Patients who are pregnant or planning to become pregnant * Patients with a serious mental illness * Patients who are participated in clinical trials other than observational studies without therapeutic intervention. * Patients who are difficult to complete the research participation agreement * Other patients whose participation in the trial is judged by a researcher to be problematic