To assess the effectiveness of therapeutic ultrasound combine transcutaneous electrical nerve stimulation (TENS) and therapeutic ultrasound in treatment of myofascial pain syndrome in upper trapezius muscle measured by mean change between pre and post treatment of pressure pain threshold (PPT), patient's complaint in pain intensity and the number of total tablet usage of acetaminophen in both groups.

Myofascial pain syndrome (MPS) is one of the most common causes of musculoskeletal pain and can affect any skeletal muscles in the body.Myofascial pain is not fatal condition but it can significant reduced quality of life and is a major cause of time lost from work. There are various treatments, which divided into invasive and non-invasive therapies. In the recent clinical practice, there is a new type of combine treatment unit which composes of electrotherapy and ultrasound therapy in one unit. However, there is no conclusive evidence for supports the effectiveness of this combine therapy compare with the conventional ultrasound in treatment of myofascial pain especially in aspect of pain relief.

Inclusion Criteria:

• Age > 20 years old
• Clinical diagnosis of myofascial trigger point pain at upper trapezius muscle(s) persisted more than 1 week but less than 6 months before recruitment time, first or recurrence episodes
• Baseline VAS more than or equal 4 at upper trapezius muscle

Exclusion Criteria:

• During the past 2 weeks had received injection or physical therapy at upper trapezius muscle or shoulder area
• Had experience of ultrasound combine transcutaneous electrical nerve stimulation (TENS)
• Had history of accidence or severe trauma to shoulder region
• Had serious musculoskeletal condition that need surgical intervention such as acute shoulder subluxation, abnormal neurological examination
• Insensate skin or sensory impairment around shoulder area
• Skin infection at shoulder area
• Had contraindication for U/S such as cardiac pacemaker, implantation, malignancy in relevant area, bleeding disorder, acute inflammatory musculoskeletal disease, pregnancy, lactation
• Unable to communication
• Unable to complete treatment session and follow protocol