If you somewhere it's allowed, go for it. Pick wisely, choose someone who is not going to start grinding their elbow into the back of your neck--dunno how I ended up in that spot, but my eyes still water at the memory.
Perhaps aim for a business from whom you can claim a health fund refund (even if you don't have a insurance) as you are more likely to find someone is is both qualified and sensible. Ask your breast care nurse for a recommendation--even if it's only advice about where she wouldn't go.
i had a delicious massage from a qualified practitioner who used a warm cup across my chest, carefully avoiding the port itself-- I could literally feel my neck relaxing. No force, no pressure, just lovely. Mxx