Many people mistakenly believe that finding a coat of arms with your surname means it’s “your” coat of arms and that you’re entitled to use it. That’s not how it works. The coat of arms may have been used by a different family with the same name. You will have to trace your line back to find out if one of your ancestors ever used it. Even that doesn’t mean that it’s yours to use.
For more information, see Ask Yvette – Does my Family have a Coat of Arms?