What does it mean if you have swollen armpits and joint pain?

Mononucleosis: Swelling under the arms and generalized pain are symptoms of mono. You should see your family doctor and perhaps get a blood test to confirm it.

Swelling in the armp: It or axilla can be a sign of lymph node involvement and arm pain associated can be a sign of infection inflammation or circulation disturbance or something more severe , if you have pain in your armpits and swollen painful arms you need to be evaluated.