I did not experience this "cord" but did have period pain, achiness, twinges, etc. in both the breast and underarm area. My oncologist told me this is nothing to worry about - as nerve endings regenerate, you will experience all kinds of sensations and it can last up to 2 years after the surgery. I am just past the 2 year mark on the lumpectomy, and almost up to the 2 year mark on the lymph node removal, and I have very little sensation anymore in those areas, just as the dr. said. But I also didn't hesitate to mention it each time I saw her, just to be sure.