Hello. Thank you for coming to JustAnswer with your question, and welcome.
Chest pain can be a symptom of many things, including the costrochondritis that you have been diagnosed with.
As for the Kava kava.....liver damage is a serious concern with the use of this herb, especially when used without a physician's supervision. Here is more information about this herb: http://www.umm.edu/altmed/articles/kava-kava-000259.htm
Mild liver damage may cause no symptoms at all, but you would want to be aware of this as a possible problem before continuing to use Kava kava. The only way to know is to see your physician to be evaluated.
However, here is some information from a trusted site about liver problems:
Just a note of warning, you may or may not be aware of this. Herbal remedies should be used with as much caution and concern as prescription medications. The problems with herbals is there are less studies usually done to forewarn you about possible side effects.