Can a doctor misdiagnose a heart attack even with an ekg, blood test, and chest x-ray all done and examined as normal?

No doctor can...: No doctor can be 100% correct in whatever he says. Likewise, no patient can be 100% correct in what he says. Humans are imperfect. The big picture is important. That means a patient can look at his entire life and write down all the things that are very suspicious for heart disease in his age-sex-weight-lifestyle group, and ask the doctor what the likelihood of heart disease is with that data.