I used to wear a port in my upper thigh (ages 14-18) which was fantastically convenient for taking care of self-medication (although I never accessed it) but dreadfully inconvenient because the area was painful and I couldn't wear jeans or participate in ball sports.
Now I have a port in my upper breast, in a place that falls right underneath the bra strap, which means I have to wear strapless bras when I have the needle and system on. And I cannot drive during that time either, because the car belt falls over the area. Inconvenient!
I have never accessed the port myself (here in Spain we go to the hospital every 7 days to change the needle and system, during an IV treatment) but it is very important for me to have clear visibility to clean it, change the adhesive, and handle the medication -- and upper chest is NOT a good place for that!
Another issue that is very important for me is that the shape of the port is rounded in a way that would prevent it from tearing the skin. After a few months in my leg, the skin tore open and I could see the port. That was rather traumatizing at age 14 (or any age), believe me! Then the port was moved a couple inches and this never happened again. But now on my chest, even though its a smaller brad port, I can feel its edges through the skin and I have to focus on thinking of something else or I would go mad with the impression and fear that the skin will tear again. So please design something with very curve edges!! No edges, please!!!
By the way, although upper chest is not a practical place, I would not choose upper arm because I really value independence (accessing it is not so crucial to me, but being able to change the adhesive without help, is!).
Keep us posted, and thanks so much for taking the time to ask us!