Painful lymph nodes in your neck are almost always a sign that your immune system is fighting an infection nearby. The nodes themselves aren’t the problem. They’re reacting to something else, whether that’s a cold, a sore throat, an ear infection, or even a dental issue. This type of tenderness is called reactive lymphadenopathy, and it’s the most common reason lymph nodes swell and hurt.
What Lymph Nodes Actually Do
Your neck contains dozens of lymph nodes arranged in chains along your jawline, behind your ears, and down the sides of your neck. They filter fluid from nearby tissues and trap bacteria, viruses, and other invaders. When they detect a threat, immune cells inside the node multiply rapidly, which causes the node to swell and become tender to the touch. That soreness you feel when you press under your jaw is essentially your immune system working overtime in a small space.
The Most Common Causes
Infection is the leading reason for painful neck lymph nodes by a wide margin. The location of the swelling often points directly to the source. Nodes under your jaw tend to react to throat and mouth infections, while nodes behind your ear respond to scalp or ear problems.
Upper respiratory infections are the most frequent trigger. A cold, the flu, strep throat, or a sinus infection can all cause noticeable tenderness in the front or sides of your neck. Ear infections, tonsillitis, and mononucleosis are other common culprits, especially in younger adults and children.
Dental problems are an overlooked cause. A tooth abscess, an infected wisdom tooth, or gum disease can produce swollen, tender nodes under the jaw or along the upper neck. If you have a toothache alongside sore lymph nodes, the two are likely connected. A tooth abscess that goes untreated can spread infection into the jaw, throat, and deeper neck tissues.
Skin infections near the head and neck, including infected cuts, acne, or conditions like impetigo, can also drain into cervical lymph nodes and make them painful.
What Painful Nodes Feel Like
Reactive (infection-related) lymph nodes are typically soft, movable, and tender when you press on them. They may feel like a rubbery marble or a small bean just under the skin. You might notice them suddenly one morning, or the tenderness might build over a day or two as an illness takes hold. Some people feel a dull ache in their neck even without touching the area, while others only notice the pain when they turn their head or press on the spot.
Nodes smaller than 1 centimeter (roughly the size of a pea) are generally considered normal, even if you can feel them. Nodes larger than 1 centimeter are conventionally classified as enlarged. During an active infection, it’s common for nodes to swell to 2 centimeters or more and still be completely benign.
How Long the Swelling Lasts
Most painful lymph nodes shrink back to normal as your body clears the underlying infection. For a typical cold or upper respiratory infection, this means the tenderness fades within one to two weeks. Some nodes stay slightly enlarged for several weeks after you feel better, which is normal. The immune system doesn’t always reset instantly.
If a node hasn’t returned to its baseline size after eight to twelve weeks, that’s worth getting checked. And if a node is still growing after four to six weeks rather than shrinking, that timeline alone is a reason to follow up with a doctor.
When Swollen Nodes Signal Something Serious
Painful lymph nodes are actually more reassuring than painless ones. Tenderness usually means the node is reacting to an infection, which is exactly what it’s designed to do. Malignant (cancerous) lymph nodes tend to be painless, firm or hard, fixed in place rather than movable, and larger than reactive nodes across all dimensions. They also tend to be rounder and grow steadily over weeks without an obvious infection to explain them.
Certain features raise the concern for lymphoma or metastatic cancer:
- Location above the collarbone. Swollen nodes in the supraclavicular area (the dip just above your collarbone) carry a high risk of being associated with abdominal or chest malignancy and need prompt evaluation.
- Systemic symptoms. Unexplained weight loss greater than 10% of your body weight, drenching night sweats, or persistent fevers without an obvious infection are red flags.
- Duration beyond six weeks with no improvement or continued growth.
- Swelling in multiple regions at once, such as your neck, armpits, and groin simultaneously.
Age also matters. In children and young adults, swollen neck nodes are overwhelmingly caused by infections. After age 40, the risk of malignancy increases, and unexplained lymph node enlargement deserves earlier investigation.
What You Can Do Right Now
If you’re in the middle of a cold, sore throat, or other obvious infection, your sore lymph nodes are doing their job. A warm compress against the side of your neck can ease discomfort, and over-the-counter pain relievers can help with tenderness. Staying hydrated and resting gives your immune system the best chance to resolve the infection quickly.
If you suspect a dental cause, pay attention to whether the tenderness is concentrated under your jaw on one side, especially if you have tooth pain, swelling in your gums, or a bad taste in your mouth. A dental abscess won’t resolve on its own and needs treatment to prevent the infection from spreading deeper into your neck.
For nodes that appeared without any obvious illness, track their size and how they feel over the next few weeks. A node that’s shrinking is almost certainly benign. A node that’s growing, feels hard, doesn’t move when you push it, or comes with any of the systemic symptoms listed above warrants a visit to your doctor, who can determine whether imaging or a biopsy is needed.