When to worry about enlarged lymph node under arm

When should I worry about a lymph node under my arm?  I've had a pea-sized enlarged lymph node since I was in college, over 30 years ago.  At that time doctor was not worried.   Now suddenly the doctors at my clinic are worried about it.   It seems harder and pointier, but so do all four enlarged pea-sized lymph nodes in my body, ever since menopause.  Since menopause my breasts have shrunk and sagged, my skin is dry and saggy, and little of my body has as much fat under the skin.

I had a mammogram done, and technician says they may do an ultrasound just because it's a "lump".   On the ultrasound it looks rather kidney-bean shaped to me - albeit from the back.  

Online it says to panic about every enlarged lymph node under an arm if one is female.

If it was cancer, wouldn't it really have grown in 30 years?

[zouzi]

Hi,
The lymph nodes, which are located in different parts of the body including the neck and armpit, are a part of the lymphatic system.When a lymph node becomes swollen, it usually indicates infection.
The normal size of a lymph node can range from a couple of millimeters to about a centimeter.When there is infection or inflammation somewhere in the body, a lymph node may enlarge and can remain enlarged for a very long time and even never disappear completely,but it doesn't necessarily mean it's something bad.
Since you had this enlarged lymph node for so long,I doubt that it could be something terribly wrong with it,but since changes have been detected, it's a good thing to have the lump evaluated.
Depending of course on what your doctor deems appropriate he/she may recommend (After the Ultrasound) to just monitor the lymph node growth every 3 or 6 months,or perhaps ordering more investigative test to rule out malignancy.
I truly hope that there is nothing serious at all.
Wishing you all the best....