Hi Sukie, welcome to the site. My first recurrence also involved the supraclavicular nodes and in my neck and at base of neck. Before confirmation by biopsy I had a lot of pain and swelling in that shoulder and arm, which was then compounded by the biopsy. I didn't think my arm would ever be normal again, but after a few months of Herceptin/Navelbine the pain was virtually gone, and I was left with just mild lymphedema to the arm, which is easily controlled. So hang in there, with effective treatment of the mets this should reduce the pressure on the affected nerves and quality of life should improve.
I myself have a port, have had it since that first recurrence in 2001 as the Navelbine is quite hard on the veins. But, in between chemos I've been on Herceptin alone and find the port makes life so much easier. I would recommend you talk to some of the patients at your treatment center who have ports and see what they think. It's probably going to be necessary at some point that you receive chemo in combination with the Herceptin and if your port is already in place it will just make it easier on you when/if that time arrives, especially since you already have "wobbley" veins. They're only going to get wobblier
If you are scanned again after an interval of Herceptin and find it's working to keep the cancer contained or even shrinking it, that will be great! But if you continue to have progression ie: areas enlarging or new areas of concern, keep in mind that chemo for mets is generally easier to tolerate than chemo for primary disease in that the goal is containment and good quality of life.
Keep us posted on your progress and good luck!
<3 Lolly