Pain in the back left side of your head is most often caused by muscle tightness or nerve irritation at the base of the skull, not something dangerous. The muscles and nerves in this area are surprisingly sensitive to posture, stress, and tension, and they can produce pain that ranges from a dull ache to sharp, electric jolts. Understanding the specific pattern of your pain helps narrow down what’s going on.
Muscle Tension and Trigger Points
The most common explanation is tension in the small muscles at the base of your skull, called the suboccipital muscles. These muscles control fine head movements and sit right where you’re feeling pain. When they get tight or develop trigger points (knots of contracted muscle fiber), they generate pain at the base of the skull that can extend down the neck and into the shoulders. The pain is typically a steady ache or a feeling of pressure, and it tends to worsen through the day, especially if you spend hours looking at a screen.
The upper trapezius muscle, which runs from your neck to your shoulder, can also refer pain to the back of your head on one side. A trigger point on the left side of this muscle often sends pain up into the left shoulder and base of the skull. If you notice the pain worsens when you press on a tender spot in your neck or shoulder, muscle tension is the likely culprit.
How Posture Plays a Role
Forward head posture, the position your head drifts into when you’re hunched over a phone or laptop, increases compressive loading on the joints and ligaments of your cervical spine. Over time, this causes the muscles at the back of the neck to shorten and tighten while other supporting muscles weaken. The result is increased pressure on the joints, nerves, and soft tissue at the top of your spine, which translates directly into pain at the base of your skull.
Rounded shoulders and a curved upper back make this worse. The combination compresses the uppermost vertebrae that support your head and can irritate the nerves passing through that area. If your pain tends to build during work hours and eases on weekends or when you’re moving around, posture is probably a major contributor.
Occipital Neuralgia
If the pain feels sharp, piercing, or like an electric shock running along one side of your scalp, it may be occipital neuralgia. This happens when one of the occipital nerves, which carry signals from the brain through the scalp, gets pinched or irritated. The pain can start at the back of your head and shoot forward, sometimes settling behind one eye. It can also feel like burning or intense throbbing.
The most common cause is a pinched nerve from muscle tightness, though it can also develop after a head or neck injury. The pain often comes in sudden bursts and can be triggered by turning your head, lying on a pillow, or even brushing your hair on the affected side. If a doctor suspects occipital neuralgia, they may use a nerve block (a targeted injection near the nerve) both to confirm the diagnosis and to provide relief. If the injection reduces or eliminates the pain, it confirms the nerve is the source.
Cervicogenic Headaches
Sometimes pain in the back of your head actually originates in your neck. Cervicogenic headaches are caused by problems in the upper cervical spine, specifically the top three vertebrae (C1 through C3). Issues with the bones, discs, or joints in this area send pain signals upward into the head. The pain is typically one-sided, doesn’t switch sides, and gets worse with certain neck movements or sustained positions.
What sets cervicogenic headaches apart is that the pain clearly links to your neck. You might notice it starts after sleeping in an awkward position, after long drives, or after activities that strain your neck. Pressing on certain spots along your neck may reproduce or worsen the headache.
Migraine in the Back of the Head
Migraines don’t always hit the front of your head or behind your eyes. The pain often starts in the front and temple area but can spread to the back and sides of the head, and any region of the head or face can be affected. Up to 75 percent of people with migraines also report tightness, stiffness, or throbbing pain in the back of the neck on one or both sides during an attack.
If your pain is throbbing, lasts hours to days, and comes with sensitivity to light or sound, nausea, or visual disturbances, migraine is worth considering even though the pain is in the back of your head. Migraines also trigger the tear ducts and sinuses through nerve activation during an attack, so watery eyes or a stuffy nose on the painful side doesn’t necessarily mean it’s a sinus problem.
Simple Relief That Helps
For tension-related pain, a few targeted stretches can make a noticeable difference:
- Suboccipital stretch: Lie on your back with a small rolled towel placed at the base of your skull. Gently tuck your chin until you feel a stretch at the base of the skull and upper neck. Hold for 5 seconds, relax, and repeat 10 times. Do this twice a day.
- Neck retraction: Sitting or standing, pull your head straight back (like making a double chin) while keeping your eyes and jaw level. Repeat 15 times, twice a day.
- Lateral neck flexion: Slowly tilt your head toward one shoulder, hold for 3 seconds, then tilt to the other side. Repeat 10 times on each side, twice a day.
These stretches target the muscles most responsible for posterior head pain. They work best when done consistently over days and weeks, not just when pain flares. Applying heat to the base of your skull for 10 to 15 minutes before stretching can help the muscles release more easily.
Pain Patterns That Need Urgent Attention
Most one-sided head pain at the back of the skull is benign, but certain patterns signal something more serious. The key warning signs to watch for:
- Sudden, maximum-intensity pain: A headache that hits peak severity within seconds (sometimes called a thunderclap headache) can indicate a vascular problem like an aneurysm and needs emergency evaluation.
- Neurological changes: Weakness in an arm or leg, new numbness, slurred speech, double vision, trouble with balance or coordination, or vertigo alongside head pain could point to a vertebral artery dissection or stroke.
- Fever, night sweats, or unexplained weight loss alongside new head pain suggest a systemic illness driving the headache.
- New headache type after age 50: A first-time headache pattern appearing later in life is more likely to have a secondary cause.
- Steady worsening: Pain that progressively becomes more severe or more frequent over weeks, rather than coming and going, warrants investigation.
Vertebral artery dissection, though rare, deserves specific mention because it causes severe one-sided headache and neck pain. It can follow neck injuries, chiropractic manipulation, or even forceful coughing. If head pain comes with dizziness, hearing changes, or any stroke-like symptoms, that combination needs immediate medical attention.