From
here.
"Costochondritis is an inflammation of the junctions where the upper ribs join with the cartilage that holds them to the breastbone or sternum. The condition causes localized chest pain that you can reproduce by pushing on the cartilage in the front of your ribcage. Costochondritis is a relatively harmless condition and usually goes away without treatment. The cause is usually unknown."
There is a lot more info at that site, ten pages or so.
Since it's a connective tissue thing and not the intercostal muscles, this may do nothing, but I figured I'd throw it out there. My chiropractor did this treatment to me a few time to relieve tightness in the chest at the sternum to help with asthma symptoms. Basically all he did was use the tip of his thumb between the ribs at the sternum, and press down at a right angle to the sternum (not much pressure required at all, you'll feel it when it works). It was like it worked out nodes or kinks in the intercostal muscles.
However, I have to say that it was literally the
worst pain I've felt. I have extensive tattoos on one kneecap, ankle, shin, and elsewhere, have broken a hand, have sustained three serious dog bites, have been hit with lots of things and run into plenty more, and I'm telling, this was the worst pain I've ever felt. I would squirm like crazy but once he let up and finished the session it was a tremendous relief to tension I hadn't even realized was there. It was also an instant aid to my posture after each session.
That of course, may do nothing for you, but worth a try. You can do it to yourself but it's not really possible to get the same stretch in your chest you would have while lying down and having someone else do it.
Sternum Pain...maybe something called Costochondritis?
