What could cause a female to have pain under the right armpit?

Pain under the right armpit in a female can arise from many causes—some are harmless and transient, while others warrant prompt medical attention. Below is a comprehensive overview of possible reasons, arranged by category, to help you understand what might be going on. Remember, this information is educational and does not replace professional medical advice. If you experience severe, rapidly worsening, or life-threatening symptoms, please seek immediate care and speak to a doctor.

1. Musculoskeletal Causes

• Muscle strain or overuse
– Lifting heavy objects, carrying bags, or repetitive motions (e.g., swimming, tennis) can strain the muscles around the shoulder and armpit.
– Pain is often localized, worsens with movement, and may improve with rest and over-the-counter pain relievers.

• Myofascial pain syndrome
– Trigger points in the chest wall or back muscles refer pain to the armpit.
– You may feel tight bands of muscle; massage and stretching often help.

• Costochondritis
– Inflammation of the cartilage connecting ribs to the breastbone can radiate under the armpit.
– Worse with deep breathing, twisting, or pushing on the front of the chest.

2. Lymphatic and Glandular Causes

• Swollen lymph nodes (lymphadenopathy)
– Commonly due to infection in the arm, chest, or breast (e.g., bacterial skin infection, viral illnesses).
– Nodes feel like firm bumps; may be tender or mobile.

• Lymphoma or other malignancies
– Persistent, painless lymph node enlargement with night sweats, weight loss, or fever.
– Requires prompt medical evaluation and possible biopsy.

3. Skin and Subcutaneous Causes

• Folliculitis or abscess
– Infection of hair follicles or sweat glands (hidradenitis suppurativa) can form red, tender bumps.
– May require antibiotics or drainage if large and painful.

• Shingles (Herpes zoster)
– Reactivation of chickenpox virus causes a band-like rash and burning pain.
– Early symptoms include tingling or sharp pain before rash appears; antiviral therapy works best if started early.

4. Breast-Related Causes

• Mastitis or breast abscess
– Common in breastfeeding women; presents with breast and armpit pain, redness, and fever.
– Treated with antibiotics and continued milk drainage.

• Breast cancer
– Tumors in the outer breast quadrant can press on lymph nodes or nerves, causing armpit discomfort.
– Look for a lump in the breast, skin changes, or nipple discharge; report any concerning signs to your doctor.

5. Neurological Causes

• Brachial plexus irritation (e.g., "burner" or "stinger")
– Sudden stretch or compression of nerves at the neck-shoulder junction (common in contact sports).
– Sharp, burning pain radiates from neck into armpit and arm; usually improves quickly but may recur.

• Thoracic outlet syndrome (TOS)
– Narrowing of the space between collarbone and first rib compresses nerves or blood vessels (Illig & Doyle, 2010).
– Symptoms include aching pain, numbness, and weakness in the arm, sometimes worse when carrying items.

6. Referred Pain from Internal Organs

• Gallbladder disease (e.g., gallstones, cholecystitis)
– Right upper abdominal pain can refer to the right shoulder or armpit via the phrenic nerve.
– Often accompanied by nausea, vomiting, fever, and worse after fatty meals.

• Liver conditions
– Although less common, liver inflammation or enlargement (e.g., hepatitis, cirrhosis) can cause upper right abdominal and back discomfort that sometimes extends under the arm (Foucher et al., 2006).
– Symptoms include fatigue, jaundice, and dark urine.

7. Vascular Causes

• Paget–Schroetter syndrome (effort thrombosis)
– Blood clot in the deep veins of the arm, often after intense exercise or overhead activities.
– Presents with swelling, blue-tinged skin, and severe pain; requires urgent treatment to prevent complications.

• Aneurysm or vascular malformation
– Rarely, an abnormal bulge in an artery near the shoulder can press on nearby structures.
– May feel pulsatile or cause throbbing pain.

When to Worry

Seek immediate medical help or call emergency services if you have: • Severe, sudden pain in the armpit and chest or difficulty breathing
• High fever, chills, rapid heart rate, or skin that looks infected (red, hot, swollen)
• Signs of blood clot: arm swelling, skin discoloration, rapid worsening of pain
• Lump that grows quickly, associated weight loss, night sweats, or persistent fatigue

Not sure what might be causing your armpit pain? Use Ubie's free AI symptom checker to quickly assess your symptoms and learn about potential causes and recommended next steps.

Management and When to See a Doctor

• Home care for mild musculoskeletal pain:
– Rest, ice packs, gentle stretching, and non-steroidal anti-inflammatory drugs (NSAIDs).
– If pain persists beyond 1–2 weeks or worsens, consult your physician.

• Infection-related pain:
– If you notice fever, red streaks, or large, tender lymph nodes, contact your doctor promptly. Antibiotics may be needed.

• Persistent or unexplained pain:
– Any pain that does not improve with self-care in 1–2 weeks or is associated with systemic symptoms (fever, weight loss) should be evaluated.

• Specialist referral:
– Your primary care provider may refer you to orthopedics, neurology, dermatology, or a breast specialist depending on the suspected cause.

Always speak to a doctor if you experience any life-threatening symptoms or if you're uncertain about the seriousness of your pain. Early evaluation and treatment can prevent complications and help you get back to your daily activities sooner.