Here are a few links that explain Costochondritis, Tietze Syndrome, Chronic Costochondritis, and the MS Hug.
I also included a link that discusses other conditions related to having along with Chronic Costochondritis.
http://en.m.wikipedia.org/wiki/Costochondritis http://
en.m.wikipedia.org/wiki/Tietze_syndrome http://www.medicinenet.com/
script/main/mobileart.asp?articlekey=6171
http://chronicfatigue.about.com/od/whyfmscfsarelinked/a/costochondritis.htm
http://www.*************.com/multiple-sclerosis/c/67078/67113/ms-hug/
I've had costo quite a few times. One way I tell is that in the affected area, the space between the ribs is very sore to the touch. I expect to see a big bruise but there isn't one.
Also, costo is in one or more very distinct spots. Move an inch or so left or right and it doesn't hurt.
ess
I was diagnosed with costo while still working and I still have the films. and now convinced now that it was the hug instead.
I don't know the answer, but I have wondered this many times. I will be interested to see what others say.