What Are the Possible Causes of Left Armpit Pain Without a Lump?

There are several reasons why you might feel pain in your left armpit even if you don’t notice any lump. One common cause is muscle strain. If you use your arm a lot or lift heavy objects, the muscles around your armpit can become sore. Another possibility is irritated or pinched nerves. Nerves run through the armpit area, and sometimes they can be stretched or squeezed, causing sharp or aching pain without a visible mass. If you have had surgery, such as a procedure involving lymph node removal for breast cancer, scarring and nerve injury in the axillary (armpit) area may lead to persistent pain even when no lump is felt. Infections or inflammation in the tissues can also cause discomfort. Lastly, some people experience what is called nonspecific arm pain, meaning that the pain does not come from one clear source but may be related to everyday activities or body posture. If the pain does not go away or worsens, it is a good idea to talk with your doctor to find out what is causing it and decide how best to help you feel better.