Medically reviewed by Jane Kim, MD You may have swollen armpit lumps due to infections, cysts, or vaccines.In severe cases, some armpit lumps could be a sign of breast cancer or other conditions.Talk ...

When you feel a lump in your breast, it's understandable to be concerned. But don't jump to conclusions. Instead, take action. Call your doctor to find out what it is. Also, make sure you know the ...