A sore throat that affects only one side usually points to a localized issue rather than a general infection like a cold or flu. When both sides hurt, a virus is the most likely explanation. But one-sided pain narrows the list to conditions that target a specific structure, whether that’s a tonsil, a lymph node, a salivary gland, or even a nerve.
Tonsillitis and Peritonsillar Abscess
The most common culprits behind one-sided throat pain are infections involving the tonsils. While standard tonsillitis often affects both sides, infection can hit one tonsil harder than the other, especially if one has deeper crevices where bacteria collect. The pain is typically sharp when swallowing and may radiate to the ear on the same side.
A more serious version is a peritonsillar abscess, which is a pocket of pus that forms in the tissue next to the tonsil. This develops when a bacterial throat infection spreads beyond the tonsil itself. The hallmark signs are intense one-sided throat pain, difficulty swallowing (sometimes severe enough to cause drooling), and a muffled “hot potato” voice caused by swelling in the soft palate. Nearly all cases involve some degree of difficulty opening the mouth fully, because the inflammation spreads to the jaw muscles near the abscess. On examination, the soft tissue on the affected side looks swollen and red, the tonsil is pushed toward the center of the throat, and in about half of cases the uvula visibly deviates away from the painful side. Swollen lymph nodes under the jaw are almost always present, and some people tilt their head toward the affected side without realizing it.
A peritonsillar abscess needs medical treatment to drain the pus and clear the infection. If you’re having trouble breathing, can’t swallow liquids, or are drooling because swallowing is too painful, that warrants immediate care.
Swollen Lymph Nodes
Your neck contains clusters of lymph nodes that drain specific areas of the head and throat. When an infection develops on one side, whether it’s a bad tooth, an ear infection, or a localized throat infection, the lymph nodes on that same side swell in response. This can feel like a tender, marble-sized lump under your jaw or along the side of your neck, and the swelling itself can create a sore, aching sensation in the throat. Most of the time, the nodes shrink back to normal once the underlying infection clears.
Acid Reflux at Night
Gastroesophageal reflux disease (GERD) can cause one-sided throat soreness, particularly if you sleep on the same side each night. When stomach acid backs up into the throat while you’re lying down, gravity directs it toward whichever side is lower. The result is irritation and rawness that’s worse in the morning and concentrated on one side. If your sore throat is consistently worse when you wake up and improves as the day goes on, reflux is worth considering, especially if you also experience heartburn or a sour taste in your mouth.
Salivary Gland Stones
Small mineral deposits can form inside the ducts of your salivary glands, partially or fully blocking saliva flow. The submandibular glands, located beneath your jaw on each side, are the most commonly affected. A stone in one of these glands causes a dull, intermittent pain in the mouth or throat on that side, along with swelling that flares up and subsides. The telltale sign is intense pain during meals, when saliva production ramps up but has nowhere to go. That pain typically lasts one to two hours before easing. Sometimes the area around the stone becomes infected, adding redness, heat, and fever to the mix.
Glossopharyngeal Neuralgia
This is a rare nerve condition, but it produces a very distinctive pattern. The glossopharyngeal nerve runs through the back of the throat, and when it misfires, it sends sudden bursts of severe, stabbing or electric-shock pain to one side of the throat, the base of the tongue, or deep in the ear. Each episode lasts only a few seconds to two minutes, but the intensity is extreme. The pain is triggered by everyday actions: swallowing, coughing, yawning, or talking. Both hot and cold liquids can set it off. If your one-sided throat pain comes in sharp, brief jolts rather than a constant ache, this is a possibility worth discussing with a doctor.
Thyroid Inflammation
Subacute thyroiditis, an inflammation of the thyroid gland, is an underrecognized cause of one-sided throat pain. Because the thyroid sits in the front of the neck just below the throat, swelling on one side can feel remarkably similar to a sore throat. The pain often spreads to the ear and comes with systemic symptoms like fatigue, low-grade fever, and general achiness. It’s frequently misdiagnosed as a recurring throat infection because the throat pain dominates the picture and the thyroid connection isn’t immediately obvious.
When One-Sided Pain Could Be Something Serious
Cancers of the tonsil and surrounding throat tissue typically show up as persistent one-sided symptoms. The pain doesn’t come and go with a viral illness; it lingers for weeks. Key warning signs include unexplained weight loss, difficulty swallowing that gradually worsens, persistent hoarseness, a sensation of a mass in the throat, or ear pain on the same side. Some people notice no pain at all and are only flagged because one tonsil looks noticeably larger than the other, or because a hard, painless lump appears in the neck from a swollen lymph node.
HPV-related tonsil cancers tend to appear in younger patients who may not have traditional risk factors like heavy smoking or drinking. HPV-negative tonsil cancers are more common in older men with a history of tobacco use. The tonsils have a rich network of lymphatic drainage, so these tumors sometimes reveal themselves first as an enlarged neck node rather than throat pain.
A sore throat that lasts more than two weeks on one side, especially with any of the symptoms above, is worth getting evaluated. The vast majority of one-sided sore throats turn out to be infections or minor irritation, but persistence is the dividing line that separates everyday causes from the ones that need closer attention.