Upper arm muscle pain in the right arm is mostly due to nerve compression or surrounding muscle injury, and it is recommended to go to the hospital for MRI of the cervical spine or shoulder joint to confirm the diagnosis. 1. Nerve compression: when cervical spondylosis compresses the nerves innervating the neck, neck pain will occur, and in severe cases, radiating pain in the upper arm will occur; when the brachial plexus nerve is compressed, pain in the upper extremity will occur, and there may be no obvious neck pain. 2. Muscle injury: it occurs mostly in violent sports or shoulder muscle degeneration, rotator cuff tear occurs, resulting in shoulder pain or activity limitation and radiating to the upper arm region leading to pain. Chronic injury to the upper arm muscles caused by excessive muscle tension due to long-term strain or physical exercise, resulting in localized inflammation, can also lead to muscle pain. Treatment: symptomatic treatment, you can follow the doctor’s instructions oral non-steroidal anti-inflammatory drugs (such as ibuprofen, etc.), local topical application of creams to activate the blood, to avoid the effects of cold and so on. Right arm muscle pain in the upper arm may also have many other reasons, it is recommended to identify the cause of medical treatment, targeted treatment.