swelling in arm pit -- am I right to be very concerned?

[Jane]

I had a bilateral mastectomy in 2005; cancer was in my right breast and 3 nodes. Left breast was removed prophylactically, no lymph nodes taken on that side. I've had no problems or issues at all -- until now.

I noticed this week that there is swelling in my left armpit. I also have a vague pain there from time to time, but do not feel a lump of any kind. Due to my history, I'm quite concerned but can't get in to see anyone (my oncologist's nurse practitioner) until Nov. 26. I called my surgeon's office to see if they had an appt. open earlier—but they do not. My surgeon's nurse practitioner consulted with a physician assistant -- and called me to say just keep the Nov. 26 appt. and see what the oncologist's nurse practitioner finds.

I felt slightly blown off, perhaps incorrectly, I'm not sure. Have any of you had armpit swelling that ended up being cancer?

Jane

History:
Diagnosed 2005 at age 45, stage III, large 6 cm tumor in right breast, 3/6 nodes positive, strongly HER2+, PR+, ER+
Had chemo, radiation and one year Herceptin
Mother had breast cancer at age 45 - died at 89 years old