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Published on: 5/6/2025

What Might Be Causing a Dull Ache under My Left Armpit?

A dull ache under your left armpit can stem from a number of causes, including muscle strain, slight inflammation of lymph nodes, or even referred pain from your chest or heart area. It usually isn’t serious, but you should see a doctor if the pain lasts or comes with other worrisome signs.

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Explanation

There are several reasons why you might feel a dull ache in your left armpit. One possibility is muscle strain or inflammation from everyday activities, which is common and usually temporary. If you’ve had surgery in the area, such as axillary lymph node dissection during breast cancer treatment, the pain might be a long-term side effect where the lymph nodes or surrounding tissues remain tender. Another explanation could be referred pain from the chest. Sometimes, heart-related issues, as seen after procedures like coronary artery stent implantation, may send pain signals that are felt in the armpit. There are rare cases when infections or conditions like Lyme disease might affect nerve areas and cause discomfort, though this is less common. If the dull ache goes away with rest and over-the-counter pain relief, it’s usually not a cause for concern. However, if the pain sticks around, gets worse, or you experience other symptoms like chest pain, shortness of breath, or fever, it’s important to speak with a doctor right away.

(References)

  • Warmuth MA, Bowen G, Prosnitz LR, Chu L, Broadwater G, Peterson B, Leight G, Winer EP. Complications of axillary lymph node dissection for carcinoma of the breast: a report based on a patient survey. Cancer. 1998 Oct 1;83(7):1362-8. doi: 10.1002/(sici)1097-0142(19981001)83:7<1362::aid-cncr13;2-2. PMID: 9762937.

  • Versaci F, Gaspardone A, Tomai F, Proietti I, Crea F, Chiariello L, Gioffrè PA. Chest pain after coronary artery stent implantation. Am J Cardiol. 2002 Mar 1;89(5):500-4. doi: 10.1016/s0002-9149(01)02287-1. PMID: 11867031.

  • Gorson KC, Kolb DA, Marks DS, Hayes MT, Baquis GD. Acute brachial diplegia due to Lyme disease. Neurologist. 2011 Jan;17(1):24-7. doi: 10.1097/NRL.0b013e31820038cd. PMID: 21192188.

  • Ahuja V, Yencha MW, Lassen LF. Head and neck manifestations of gastroesophageal reflux disease. Am Fam Physician. 1999 Sep 1;60(3):873-80, 885-6. PMID: 10498113.

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