Hello sir... I have had mild chest pain for 8 months Ecg, echo and Tmt normal Lipid profile, thyroid test, , vitamin d normal Neither smoking nor drinking Daily brick walk for 40 min and running for 10 min Sir i want one suggestion with you.. Today when I walk a very mild pain feel in my left side chest  but continue to walk 30 min and after 30 min run for 10 min, but pain feel on running for starting 5 min and pain is very mild same as starting not growth and after 5 min running pain disappeared Is it any serious thing?