Yep. Sounds like cording.
If you read the literature medics appear to think it is self limiting, although that may be because it is under-reported and women simply stop complaining about it after a while!
I discussed mine, by phone, with the physio at our lymphoedema clinic, and she advised stretching and gentle massage and mine does seem to have largely resolved now. It was starting to form down below my mastectomy as well as in my arm from the AND. She actually advised against strong massage that an over-enthusiastic physio might give, as she felt it can cause more pain, but there is anecdotal evidence that "snapping" the cords can bring relief too.
As a physio myself, my advice is stretch yourself into any direction that feels tight, and hold for at least 20 seconds, adding massage to the tight areas as you so. I usually stretch in the shower and massage with my body wash. Lying on the floor is a good place. I will sometimes lie on an exercise roll placed vertically up my spine and/or add trunk rotation for extra stretch. Or you can lie on the edge of your bed, so your arm can extend over the side .....
When you stretch, any pain you have should not be increased by more than 2-3 pounts on the 10 point pain scale, I was instructed, or you risk causing more irritation and exacerbating the problem. If in doubt or needing help, try to see a physio who is experienced with lymphoedema/cording issues if possible!
