Pain under the jaw usually comes from one of a few common sources: swollen lymph nodes fighting an infection, a blocked or inflamed salivary gland, a dental problem that has spread, or muscle tension in the jaw and neck. Most cases are temporary and tied to something treatable, but the specific pattern of your pain, when it started, and what makes it worse can help narrow down the cause.
Swollen Lymph Nodes From Infection
The most common reason for pain under the jaw is swollen lymph nodes. You have a cluster of small, bean-shaped lymph nodes tucked right beneath your jawbone on each side. When your body fights off an infection nearby, whether it’s a sore throat, a cold, an ear infection, or even a dental infection, these nodes fill with immune cells and swell. They become tender to the touch and can feel like firm, marble-sized bumps that move slightly when you press on them.
Lymph nodes up to about 1 centimeter across (roughly the size of a pea) are generally considered normal. Once they grow larger than that, they’re clinically significant. In most cases, the swelling is “localized,” meaning the nodes closest to the infection are the ones that react. So pain under your jaw often points to an infection in your mouth, throat, or teeth. The tenderness typically resolves within a week or two once the underlying infection clears.
Salivary Gland Problems
Sitting just inside the curve of your jawbone on each side is a pair of salivary glands called the submandibular glands. These produce a large portion of your saliva, and they’re prone to two problems that cause pain in exactly the spot you’re wondering about.
The first is salivary stones. Minerals in your saliva can crystallize into small, hard deposits that block the duct leading from the gland to your mouth. The hallmark symptom is pain and swelling under the jaw that gets worse when you eat. This happens because eating triggers saliva production, but the stone blocks the flow, so pressure builds up behind it. The pain often eases between meals and then flares again at the next one. You can sometimes feel the stone as a hard lump if you press along the floor of your mouth toward the gland.
The second is gland infection (sialadenitis), which can develop on its own or as a complication of a blocked duct. An acute infection causes sudden pain, swelling, and significant tenderness in the gland. The area may feel firm or warm. In more severe cases, pressing on the gland can push pus out of the duct opening inside your mouth. Chronic, low-grade inflammation is also possible, causing recurring mild swelling and tenderness, particularly around meals.
Dental Infections That Spread
A tooth infection, particularly in the lower back molars (your second and third molars, including wisdom teeth), can spread into the soft tissue beneath the jaw. The roots of these teeth sit close to the floor of the mouth, and an abscess can track downward into the space under your jawbone.
Early signs include a toothache combined with tender, firm swelling beneath the chin or along the underside of the jaw. If the infection progresses, the floor of the mouth can become rigid and swollen, making it difficult to swallow or open your mouth fully. In rare but serious cases called Ludwig’s angina, the swelling can compromise the airway. This is a medical emergency. If you have pain under the jaw along with difficulty swallowing, trouble breathing, or an inability to open your mouth, seek care immediately.
Muscle Tension and Trigger Points
The digastric muscle runs along the underside of your jaw from behind the ear to the chin. It helps open your mouth and is involved in chewing and swallowing. Like any muscle, it can develop painful knots called trigger points, especially if you clench your jaw, grind your teeth at night, or hold tension in your face and neck.
A trigger point in the back portion of this muscle can send pain to the area under the chin and into the throat. One in the front portion tends to refer pain toward the lower front teeth. This type of pain often feels like a deep ache rather than a sharp or throbbing sensation, and it may worsen with prolonged chewing or stress. It’s frequently overlooked because people don’t think of the underside of the jaw as a muscular area.
TMJ Disorders
Problems with the temporomandibular joint, the hinge connecting your jaw to your skull just in front of each ear, can radiate pain in unpredictable directions. While TMJ pain most commonly shows up near the ear, in the temple, or along the side of the face, it can also refer pain downward along the jaw and into the area beneath it. Clues that TMJ might be the source include clicking or popping when you open your mouth, jaw stiffness in the morning, pain that worsens with chewing, or a feeling that your bite is slightly off. The pain tends to be on one side and may fluctuate with stress levels.
How to Tell What’s Causing Your Pain
A few questions can help you sort through the possibilities:
- Does it worsen when you eat? Pain that flares with meals and eases between them strongly suggests a salivary gland issue, especially a stone.
- Do you also have a sore throat, cold, or earache? A swollen lymph node responding to a nearby infection is the most likely explanation.
- Do you have a toothache on the same side? A dental infection spreading to the tissue under the jaw is a real possibility, particularly if a lower molar has been bothering you.
- Does it feel muscular, like a deep ache that changes with jaw movement? Muscle tension or a TMJ issue is worth exploring, especially if you’re a jaw clencher.
You can also gently feel the area. Lymph nodes tend to be round, movable, and tender. Salivary glands sit slightly deeper and feel larger, more like a walnut than a pea. A firm, immovable lump is different from both and deserves prompt evaluation.
Signs That Need Quick Attention
Most under-jaw pain resolves on its own or with straightforward treatment. But certain patterns warrant faster action. A lump that doesn’t shrink after two weeks, keeps growing, or feels fixed in place (doesn’t slide under your fingers) should be evaluated. The same goes for sores in your mouth that won’t heal, unexplained loose teeth, difficulty swallowing or breathing, or rapidly spreading swelling in the floor of your mouth. Persistent, painless lumps can occasionally signal something more serious, including salivary gland tumors or, rarely, jaw cancer. Changes in your mouth that don’t improve within two weeks are a reasonable threshold for getting checked out.