I’m not sure about a “new” small pox shot, but here is what the CDC says about the old one. It does say “persons receiving smallpox vaccine should be aware that myopericarditis is a potential complication of smallpox vaccination. If vaccinees experience chest pain, shortness of breath, or other symptoms of cardiac disease after vaccination they should seek medical attention. In addition, heart pain (angina) and heart attack also have been reported following smallpox vaccination, however, it is not known if smallpox vaccination caused these problems or if they occurred by chance alone.”
I did read that there was a new one being developed and put in a stockpile, but I’ve never read anything about it being administered to anyone yet. It’s called Imvamune. This article contains the only informations I could find about adverse reactions for Imvamune. It does mention cardiac issues, but not specifically a right axis deviation. From my understanding, it’s made specifically for people that are immunocompromised so that they may have fewer side effects.
Your best bet is to talk to your doctor (the one that gave you the shot) about what happened. If it is indeed related to the vaccination, he needs to report it.
From my understanding of right axis deviation, it is most often a congenital defect. It’s normal for some individuals because of the position of their heart in their chest. Upon further reading here, it says that chronic pulmonary disease can also be a cause of it.