Pain on one side of the vagina usually points to a localized issue rather than a widespread one. The most common culprits include a Bartholin’s cyst or abscess, a pelvic floor muscle spasm, an infection, or nerve irritation. In rare but serious cases, one-sided pelvic pain can signal an ectopic pregnancy. Most causes are treatable once identified, and a healthcare provider can often pinpoint the source with a simple physical exam.
Bartholin’s Cyst or Abscess
The Bartholin’s glands sit on each side of the vaginal opening, and a cyst or abscess almost always develops on just one side. These glands produce fluid that helps with lubrication, but if a gland’s duct gets blocked, fluid backs up and forms a cyst. A small, uninfected cyst may go unnoticed entirely. As it grows, you’ll feel a lump or mass near the vaginal opening, and the area may become tender.
If the cyst becomes infected and turns into an abscess, the pain ramps up significantly. You may notice a painful, tender lump that makes it uncomfortable to walk, sit, or have sex. The skin over the area can become red and warm. Abscesses sometimes drain on their own, but many need to be drained by a provider. Bartholin’s cysts are one of the most common explanations for “right side only” vaginal pain, especially if you can feel a distinct bump.
Pelvic Floor Muscle Spasms
The muscles that support your pelvic organs can spasm on one side, creating a deep ache or sharp pain in the vagina, rectum, or pelvis. The levator ani is a key pelvic floor muscle that runs near both the anus and vagina. When it tightens involuntarily, you may feel a dull pressure or sudden stabbing sensation that’s hard to pin down. The pain can come and go, sometimes lasting minutes, sometimes hours.
Pelvic floor spasms often worsen with sitting for long periods, during bowel movements, or after sex. Stress, injury during childbirth, and chronic straining can all contribute. Because the muscle group spans both sides of the pelvis, spasms frequently affect one side more than the other, which is why the pain can feel distinctly right-sided. Pelvic floor physical therapy is one of the most effective treatments.
Localized Vulvodynia
Vulvodynia is chronic vulvar pain without a clear identifiable cause like an infection or skin condition. The localized form, which is more common than the generalized type, concentrates pain in a specific area, most often the vestibule (the tissue surrounding the vaginal opening). This means you can have significant pain on the right side of your vestibule while the left side feels completely normal.
The hallmark of localized vulvodynia is pain triggered by touch or pressure: inserting a tampon, having sex, or even wearing tight clothing. Providers diagnose it using a cotton swab test, gently pressing specific points around the vestibule (mapped like positions on a clock face) and asking where and how intensely you feel pain. Pain at certain positions confirms the diagnosis. Treatment typically involves pelvic floor therapy, topical medications, and sometimes nerve blocks.
Infections
Several types of infection can cause pain that feels one-sided. Yeast infections and bacterial vaginosis usually cause more widespread discomfort, but a localized boil, ingrown hair, or infected skin gland on one side of the vulva can create a focused pain point. Herpes outbreaks also tend to appear in clusters on one side, causing burning or stinging in a specific area along with small blisters or sores.
Pelvic inflammatory disease (PID) is a deeper infection that affects the uterus, fallopian tubes, or ovaries. PID can cause lower abdominal pain that may be worse on one side if the infection is concentrated in one fallopian tube or ovary. Other signs include unusual discharge with a bad odor, pain or bleeding during sex, burning when you urinate, and fever. PID is caused by sexually transmitted bacteria and needs prompt antibiotic treatment to prevent long-term damage to your reproductive organs.
Pudendal Nerve Irritation
The pudendal nerve runs through the pelvis and supplies sensation to the vulva, vagina, and surrounding area. When this nerve is compressed or irritated, often by surrounding muscles or tissues, it can produce stabbing, burning, or shooting pain. Because you have a pudendal nerve on each side, damage to the right one creates right-sided pain.
Pudendal neuralgia typically worsens with sitting and improves when you stand or lie down. The pain may feel like a burning sensation deep inside or a sharp, electric quality near the surface. Providers diagnose it through a combination of physical exam, imaging, and sometimes a nerve block injection. If numbing the pudendal nerve eliminates your pain, that strongly suggests the nerve is the source. Treatment ranges from physical therapy and lifestyle modifications to nerve block injections for more persistent cases.
Endometriosis
Deep infiltrating endometriosis occurs when tissue similar to the uterine lining grows into structures outside the uterus, including the vaginal wall, the space between the uterus and rectum, and the bowel. These growths can form nodules that create focal pain in specific locations, including one side of the vagina. The pain tends to be worst during periods, during sex (especially with deep penetration), or during bowel movements.
If your right-sided vaginal pain consistently flares around your menstrual cycle or with specific activities like sex or passing stool, endometriosis is worth investigating. Diagnosis often requires imaging or surgery, and treatment includes hormonal therapies or surgical removal of the endometrial tissue.
When the Pain Is an Emergency
Most causes of one-sided vaginal pain are not dangerous, but a few demand immediate attention. An ectopic pregnancy, where a fertilized egg implants outside the uterus (usually in a fallopian tube), causes pelvic pain that’s often sharply one-sided. Early signs include light vaginal bleeding and pelvic pain. If the ectopic pregnancy ruptures, symptoms escalate to severe abdominal pain, extreme lightheadedness, fainting, and even shoulder pain from internal bleeding irritating the diaphragm.
Seek emergency care if your one-sided pain comes with any of these: excessive vaginal bleeding, fever, nausea or vomiting, or signs of shock like fainting or feeling like you might pass out. Sharp, sudden pelvic pain that feels different from anything you’ve experienced before also warrants urgent evaluation.
What to Expect at the Doctor
A provider evaluating one-sided vaginal pain will start by asking about timing (constant versus triggered by touch, sex, or your period), associated symptoms, and your sexual and reproductive history. The physical exam may include a cotton swab test, where the provider gently touches specific points around the vulvar vestibule to map exactly where the pain is and how severe it feels. This simple test can distinguish vulvodynia from other conditions.
Internal palpation lets the provider check for Bartholin’s cysts, pelvic floor muscle tenderness, ovarian enlargement, or masses. They may also gently move the cervix to check for the tenderness that signals pelvic inflammatory disease. Depending on what the exam reveals, next steps could include swabs for infection, ultrasound imaging, or a referral to a pelvic floor specialist. Many of the most common causes, including Bartholin’s cysts, infections, and pelvic floor dysfunction, are highly treatable once correctly identified.