I so sympathise, just got over doing something which may be what you have done. http://forums.teamestrogen.com/showthread.php?t=45755

Costochondritis is so painful, even to sniff, rolling over in bed was a no-no! I was beginning to think it would never ever ease up, it took around 6 weeks.

In desperation saw my chiropractor for advice and she suggested to get Naproxen from GP, gentler than diclofenic sodium. I dislike taking any medication but it did help, just for a few days. Oh yes, I also used Biofreeze just below my collar bone, which is where the worst damage was.

The first exercise I started a few weeks later was swimming, I must have looked weird as I could only do breast stroke with one arm! Little by little I was able to swim with both arms, then ride.

This shows my ignorance but I did not realise how high the rib cage went up but I do now.

Hope it starts easing up for you very soon.