Hi Cowanna,
I too have Costocondritis and I am sorry to say have been struggling also. I too had all sorts of Heart Tests completed and thankfully have no heart issues, but my anxiety has taken these symptoms and run with them, creating a mess of a mental situation. I have been trying some cupping, and massage, and it helps for a bit, but comes right back.
I guess I am commenting to say you aren't alone, and I would be happy to talk with you about what we both experience and share anything that might be helpful!
Amanda