Using Different Amplitude-modulated Frequencies of IFC for the Treatment of Trigger Points

Inclusion Criteria: * males or females, * 17 - 50 years of age, * unilateral pain in the cervical, neck, and upper shoulder, pain persists for 3 months or more, * pain should be not less than 2 on the visual analog scale (VAS), * having positive signs of chronic (latent) trigger point(s) in the upper trapezius muscle Exclusion Criteria: * cervical and or shoulder pathologies such as disc lesions, arthritis, or compression problems. * neurological symptoms in the upper limb such as radiculopathy. * previous cervical, thoracic, or shoulder surgery. * regular sports practice. * heavy work-related activities. * trauma to the cervical spine (whiplash injury). * osteoporosis. * complex regional pain syndrome. * thoracic outlet syndrome * regular analgesic drugs.