High Intensity Laser Therapy (HILT) on Myofascial Trigger Points.

Inclusion Criteria: * Participants over 18 years of age. * Officials and students of the Casona las Condes Campus of the Andrés Bello University. * Presence of myofascial trigger points in the shortened upper trapezius muscle evaluated (expert consensus establishing criteria for the diagnosis of MTrPs, Delphi study).25 Exclusion Criteria: * Musculoskeletal problems or pathologies of the neck or shoulders in the last 3 months (fractures, sprains, tendinopathies, dislocations, or muscle tears). * Presence of osteosynthesis materials near shoulders, neck, or surrounding areas. * Presence of wounds or skin changes in the shoulder and/or neck region (such as psoriasis, scars, or burns). * Use of analgesic, anti-inflammatory, or muscle relaxant medications for permanent use. * Neurological changes such as paresthesia, loss of sensitivity (partial or complete), decreased strength, and color changes in the neck, arms, forearms, or hands. * Diagnosed photosensitivity. * Presence of solar urticaria or adverse reactions to sunlight. * Presence of the following conditions: dermatomyositis, systemic lupus erythematosus, hepatic porphyria, cutaneous carcinoid syndrome or pellagra * Cancer or tumors of any type diagnosed. * Epilepsy.