CDC looking into reports that a small number of teens and young adults vaccinated against the coronavirus that may have experienced heart problems Condition, known as myocarditis, results in an inflammation of the heart muscle which can occur following certain infections Problems have been occurring four days after the second dose has been given Dozens of cases have been reported to the agency in recent week It is not yet clear which vaccine might be responsible, Moderna or Pfizer The agency's vaccine safety group was sparse in details, saying only that there were 'relatively few' cases and levels were similar...