Pain on the sides of your neck is most often caused by muscle strain, particularly in the large muscles that run from behind your ears down to your collarbones. Less commonly, swollen lymph nodes, nerve irritation, or vascular issues can be responsible. Neck pain affects roughly 203 million people worldwide, with women experiencing it about 40% more often than men, and the highest rates falling between ages 45 and 74.
The sides of your neck contain a dense layering of muscles, lymph nodes, nerves, and blood vessels. Figuring out which structure is generating your pain helps you understand whether it will resolve on its own, needs a simple change in habits, or warrants a medical evaluation.
Muscle Strain: The Most Common Cause
The sternocleidomastoid (SCM) is the thick muscle you can feel on each side of your neck when you turn your head. It runs from the bony bump behind your ear down to your collarbone and breastbone, and it’s involved in nearly every head movement you make. When this muscle develops tightened, sensitive knots called trigger points, the result is a dull or sharp ache along the side of your neck that can persist for days or weeks.
What makes SCM pain tricky is that it often shows up somewhere other than the muscle itself. You might feel it in your forehead, behind your eye, in your ear, cheek, or throat when you swallow. Other symptoms tied to an irritated SCM include headaches, dizziness, neck stiffness, and even a droopy or watery eye on the affected side. People sometimes mistake these for sinus problems or migraines because the pain radiates so far from its source.
The scalene muscles, a smaller group that sits just behind and beneath the SCM, are another frequent culprit. They help tilt your head to the side and assist with breathing, so they’re active all day long. When strained, they produce pain along the side of the neck that can radiate into the shoulder and down the arm.
What Triggers Lateral Neck Muscle Pain
Poor posture is the leading driver. When your head drifts forward, as it does when you look down at a phone or hunch over a laptop, the load on your cervical spine increases dramatically. An adult head weighs about 10 to 12 pounds in a neutral upright position, but tilting it forward just 15 degrees raises the effective load to roughly 27 pounds. At 30 degrees, it jumps to 40 pounds. At a 60-degree angle, common when scrolling through a phone in your lap, the muscles in your neck are supporting the equivalent of 60 pounds.
Stress and anxiety also play a direct role. Many people unconsciously clench or elevate their shoulders when they’re tense, which keeps the SCM and upper trapezius in a shortened, contracted state for hours. Sleeping on your stomach forces your head into a rotated position all night, which can leave one side of your neck stiff and sore by morning. Certain occupations carry extra risk as well: violinists, painters, carpenters, and anyone who holds their head in an awkward position for long stretches can develop chronic SCM strain.
Swollen Lymph Nodes
A chain of lymph nodes runs along each side of your neck, and when they swell, the pain is usually easy to distinguish from muscle soreness. You’ll feel one or more tender, marble-sized lumps just under the skin. They may be sore to the touch or ache on their own, and the overlying skin can feel warm.
Infection is the most common reason for swollen cervical lymph nodes. A cold, flu, sore throat, ear infection, or dental abscess causes nearby lymph nodes to ramp up their immune response, which makes them enlarge and become tender. This kind of swelling typically resolves within one to two weeks as the infection clears. Autoimmune conditions can also cause persistent lymph node enlargement, and in rare cases, painless swelling that doesn’t go away points to something more serious that should be evaluated by a doctor.
Carotid Artery Tenderness
A less well-known cause of one-sided neck pain is carotidynia, an inflammatory condition affecting the carotid artery. The carotid arteries run up each side of your neck, and when the tissue around one becomes inflamed, you feel a throbbing ache on that side that can radiate up to your ear. The pain typically gets worse when you swallow, chew, or turn your head. You might also notice a stronger-than-usual pulse on the affected side.
Carotidynia is uncommon, and episodes generally resolve within two weeks. It’s diagnosed when imaging rules out structural problems in the artery itself. If you feel a pulsing, throbbing pain on one side of your neck that’s tender to the touch and worsens with head movement, it’s worth getting checked to rule out other vascular issues.
Stretches That Help Lateral Neck Pain
For muscle-related pain, targeted stretching of the SCM, scalenes, upper trapezius, and levator scapulae (the muscle that connects your shoulder blade to the top of your neck) can provide real relief. Here are three to start with:
- SCM stretch: Sit or stand upright. Tilt your head to the right, bringing your right ear toward your right shoulder. Then rotate your chin slightly upward and to the left. You should feel a gentle pull along the left side of your neck, from your collarbone to behind your ear. Hold for 20 to 30 seconds and repeat on the other side.
- Scalene stretch: Sit tall and gently grasp the edge of your chair with your left hand to anchor your shoulder down. Tilt your head to the right and slightly backward. You’ll feel the stretch along the front-side of your neck. Hold for 20 to 30 seconds per side.
- Upper trapezius and levator scapulae stretch: Tilt your head to the right, then rotate your chin downward toward your right armpit. Use your right hand to apply gentle pressure on the back of your head. The stretch should run from the base of your skull down to your shoulder blade. Hold for 20 to 30 seconds per side.
Perform these once or twice a day. If any stretch increases your pain or produces tingling, stop.
Posture and Sleep Adjustments
Position your computer monitor or laptop at eye level so your head stays in a neutral position rather than tilting forward. When using your phone, bring it up to eye level rather than dropping your chin to your chest. If your work requires holding awkward head positions for long periods, take breaks every 30 minutes to gently move your neck through its full range of motion.
Sleep position matters more than most people realize. Sleeping on your back with a pillow that supports the natural curve of your neck places the least strain on the lateral muscles. Side sleeping is also fine as long as your pillow fills the gap between your shoulder and head, keeping your spine roughly straight. A pillow that’s too thin lets your head drop toward the mattress, and one that’s too thick pushes it upward. Both create sustained strain on one side of your neck all night. Stomach sleeping is the worst position for lateral neck pain because it forces your head into full rotation for hours.
When Neck Pain Signals Something Serious
Most lateral neck pain improves within a few days to two weeks with stretching, posture correction, and rest. But certain symptoms alongside neck pain require prompt medical attention:
- Persistent tingling or numbness in your hands, arms, or legs, or a feeling that your limbs keep “falling asleep”
- Leg weakness or balance problems when walking
- Fever or chills alongside neck pain
- Headache with dizziness, nausea, vomiting, or light sensitivity
- Loss of bladder or bowel control
- Neck pain triggered by an accident or trauma
These red flags can point to nerve compression, infection, or spinal cord involvement, all of which need evaluation that goes beyond self-care.