Tension headaches, causing pain at the base of the neck, are the most common type of headache by a wide margin. The area between the upper cervical spine and the base of your skull is termed the sub-occipital region. This area is rich in nerve fibers, joints and small muscles -- all of which are capable of generating pain. Because this pain can indicate a life-threatening condition, see your doctor for an accurate diagnosis if you experience these symptoms.
Excessive Muscle Tension
Although not completely understood, tension headaches are assumed to be partly related to excessive muscle tension and contraction in the upper shoulders, neck, sub-occipital region and scalp. This tension is usually caused by sustained stress and poor posture, leading to inflammation and dull, achy pain. Tension headaches produce mild to moderate levels of diffuse pain distributed around the head in a band-like pattern that includes the back of the head and base of the neck.
Tension headaches may also result from changes among certain brain chemicals, such as serotonin and endorphins, which activate pain pathways and interfere with the brain's ability to suppress pain. In addition to stress and poor posture, jaw clenching, depression, dehydration and weak muscles could contribute to tension headaches and pain at the base of the neck.
Upper Neck Dysfunction
The upper cervical vertebrae in the neck are vulnerable to injury and dysfunction. These bones act as the base for the head, and are required to move in various directions. When the muscles, tendons, ligaments, joints or nerves of the upper neck are injured, pain is produced locally, but a cervicogenic headache might also develop. Cervicogenic headache is occipital or sub-occipital pain that originates from injury to nerves of the neck, often the trigeminal nerve complex, or the small joints of the neck.
Cervicogenic headache pain is usually dull and localized near the base of the head, although it can become sharp with sudden neck movements, spreading up to the top of the head. Upper neck dysfunction can be caused by osteoarthritis, rheumatoid arthritis, apophyseal joint impingement or dislocation, nerve root irritation, and bulging intervertebral discs. Trauma, such as neck whiplash from a car accident, poor posture, stress, migraines and increased age all increase the probability of cervicogenic headaches and neck pain.
Disease processes can cause headaches at the base of your neck. In addition to arthritis, rarer diseases and conditions include spinal meningitis, which produces severe shooting pains up the spine into the head; brain abscesses, which can form in the occipital area of the skull; Paget’s disease, which causes bone destruction; brain tumors such as meningiomas, which could put pressure on sensitive structures at the base of the neck and head; and brain aneurysms, which can produce sudden, excruciating pain anywhere in the skull. The Centers for Disease Control and Prevention notes that both bacterial and viral meningitis often start with a headache and a stiff neck, but usually also include fever, nausea and sensitivity to light.