cfm,

Thanks for your question.  Because of the chest tenderness, this most likely is due to a musculo-skeletal cause rather than cardiac.  However, because of your active lifestyle, the safest thing to do is schedule an appointment with a physician for a check up.  During this evaluation, the doctor will take your history which will screen you for risk factors for heart disease.  Depending on these factors, your age and other information, he might suggest a cardiac stress test to be sure that it is safe to continue your juijitsu program.  If he does not mention it, you should ask about it.

When it comes to chest discomfort, you should never take chances.  Follow up on the emergency room evaluation, which just looks for acute problems.

Best wishes.

Martin Cane, M.D.