Benign reactive lymph node

I was diagnosed with stage 1 invasive ductal carcinoma in May 2005 aged 39. I had two lumpectomies, auxilla clearance (node negative) chemo and radiotherapy. I now have an enlarged lymph node on my unaffected breast. I have had MRI and Ultrasound and been told I have a benigh reactive node. I am very healthy and have had no known infections, virus's or scratches. None of my other lymph nodes are enlarged. The node is painless and palpable. I have had it for over 3 months.
My consultant (via his secretary) has asked to see me in 6 weeks instead of 4 months. If this is nothing to worry about why would this be the case?
Should I ask for a biospy?

[Cleveland Clinic]

Dear Cherylmax:  Without examination, including clinical breast examination, MRI, and ultrasound, we cannot speculate on what this might be.  You might consider sharing your concerns with your doctor.  It is often appropriate, however, for a physician to follow an enlarged lymph node to make sure it resolves or does not enlarge further.