I have similar symptoms as the question below - a swollen vein in front of my ribs on the left side disappearing under my left breast. Feels tender and ropey. 55yo female. Just had a partial mastectomy on right side and targeted radiation I finished on Friday. Both breasts were lifted. No apparent infection.
Thanks for your question on Chat Doctor. I can understand your concern. You are having thrombophlebitis. It is inflammation of vein. Tenderness and swelling suggest this. This is common after radiation therapy. Actually radiation causes destruction to cells and this causes inflammatory reaction. So take painkiller and anti-inflammatory Chat Doctor.  Apply ice packs on swollen vein. You will mostly improve in 3-4 days. But if you are not improving than consult doctor and rule out infection. Hope I have solved your query. Wish you good health. Thanks.