A person's skull, neck and shoulders are linked together by muscle and connective tissue. Pain in these areas may be caused by numerous factors, including a traumatic injury, muscle strains and deep referred pain from trigger points--hyperirritable nodules in a tight band of muscle--in other parts of the body. Pain in one these areas may be focal and unrelated to the function and health of the others, or it may be diffuse and directly related to musculoskeletal problems in one of the other areas.

Traumatic Injury

Traumatic injury can cause headaches, neck pain and shoulder pain. According to the Mayo Clinic, almost 1/2 the United States' troops assessed for chronic headaches after a tour of duty have a history of mild head trauma, often caused by exposure to blasts. The Mayo Clinic notes that headaches caused by trauma typically resolve within several weeks, although some may continue for months or even years.

The Spine Universe website states that trauma-related neck pain, especially whiplash-induced neck pain, damages the neck's soft tissues and is usually caused by rapid extension and flexion movements of the head and neck. Whiplash injuries often occur to a person who has been rear-ended while driving. Pain from severe whiplash-related neck injuries may result from damage to the following structures: intervertebral joints, discs, ligaments, cervical muscles and nerve roots.

According to the American Academy of Orthopaedic Surgeons, trauma-related shoulder pain is common and may be caused by fractures, shoulder joint dislocations and tears to the ligaments and capsule surrounding the shoulder. Common sources of shoulder trauma include falls and motor vehicle accidents.

Muscle Strains

Muscle strains may cause headaches, neck pain and shoulder pain. According to The University Health Center at the University of Georgia, tension headaches may develop from neck muscle strains, and sometimes--especially in children--incorrectly fitted glasses can cause a tension headache due to eye or ocular muscle strain.

The Spine Health website states that neck muscle strains--which involve muscle fiber micro-tears--can be painful and may be caused by a sudden force, an inappropriate sleeping position or poor posture. The website notes that while many episodes of neck pain have no identifiable anatomical cause, neck muscle strains are due to a specific soft-tissue injury involving one or more of the neck's muscles.

Muscle strains also affect the shoulder and can cause shoulder pain. Shoulder muscles strains--especially strains of the rotator cuff muscles, which stabilize and protect the shoulder joint--are common in athletes who perform whipping motions of the arm, such as baseball players, water polo players and volleyball players.

Trigger Point Pain

Trigger points can cause headaches, neck pain and shoulder pain. According to Dr. Devin Starlanyl at the FibroDoc.org website, the most common cause of headaches is referred pain from myofascial trigger points. There are numerous scalp and skull muscles in which trigger points may develop, including the frontalis, occipitalis, temporalis and the extrinsic eye muscles.

Trigger points are common in patients with musculoskeletal pain in the cervical spine. Trigger points are often located in the following neck muscles: the suboccipital group, upper trapezius, levator scapulae and splenius capitis and cervicis. Trigger points in the neck may develop and cause pain due to poor posture, stress and other factors.

Shoulder muscle trigger points can be painful and cause shoulder dysfunction. Trigger points in the shoulder muscles may refer or cause pain to appear in other parts of the body. According to the Sports Injury Bulletin website, trigger points in the subscapularis muscle--which acts on the arm to rotate it inward--could lead to satellite or remote trigger points in the muscles around the elbow and cause pain in the elbow, in addition to the shoulder.