Roemary -
I never had the collarbone area central line, so I don't know if it hurts. You might get a local for putting it in, which you DON'T for the initial stab for arm one because it causes swelling around the vein, making it hard to locate with the ultrasound. But the arm one only hurt momentarily, just one sharp stab like starting an IV with a fairly large needle, and then I was given a local which made it just fine.
I'm a little scared of the clavicle central line because there's more other stuff to hit there. But that's a personal choice, not a medical recommendation because I'm not a doctor. Both lines run a long way, to near the heart. It was so nice not to be getting stuck several times a day for blood tests.
My IV saved my life. I was starving from getting nothing by mouth (NPO), not even water, for most of a month while having a blockage after getting my ostomy. I didn't miss not eating at all, no hunger feelings, not even wanting water to drink. I felt SO much better within hours of getting total parenteral nutrition (TPN).
Ask the doc you are going to see in the west if you can keep it in his hospital. Some hospitals have stupid rules about changing lines that came from another place. I've run into that a couple of times getting transferred from an outlying hospital to one that could treat me. It could be different with central lines. I'd ask for it if I were in your position even if it would have to be changed, just to stay alive and feel healthier the next two weeks.