Costochondritis can be in the chest and ribs. When I have a flare up, if I press on the sternum, it is tender. I take ibuprofen with food and that helps me. Here is a link all about costochondritis that may help you.
Sorry about a couple of the links "being broken" that I listed above. Arrrgh! You can find those links if you Google the same keywords in the addresses listed.
I believe that the Costochondritis can be all along the Intercostal Muscle region. It could also just be the muscles that hurt, rather than the cartilage or bones being the actual problem.
I'll try again to post a link. Here's one to Wiki with a diagram of the Intercostal Muscles. You can also have pain all the way up into the front of your arm/bicep.
Diagram of the Intercostal Muscles:
Info on Costochondritis:
Hope this helps ~*~ Karen free2bfree