Armpit lymph node suddenly and painfully 6 days ago with mild sore throat.soft and like a small marble. it is still palpable. breast cancer?

May be viral: A painful lymph node that appears suddenly and concurrently with a sore throat may be part of a viral infection, but there are many other causes for axillary (arm pit) lymph nodes to be enlarged. If it does not resolve soon or gets larger, a medical exam is warranted.

Get checked: Since breast cancer does not cause throat throat, it is likely from a viral infection. If problem gets worse or persists more than 2 wks, it is best to get checked out.