Is dextrocardia congenital?
As the comments pointed out, this is not a hard question to answer with some research, but I'll add a few more details. 

Dextrocardia is congenital. The human heart normally actually isn't so much on the left side - it's more pointed towards the left. In dextrocardia it points more towards the right side. This develops within the first few weeks of embryonic development, as the heart is one of the first organs to develop. 



Source

It occurs in about 0.7 percent of live births and 2.7 percent of stillbirths, indicating that there are health problems in the fetus associated with it. After birth, it's possible that the heart functions perfectly fine, but often there are other heart defects associated with dextrocardia. 

Dextrocardia with situs inversus is a condition in which the heart and visceral  organs are reversed. As for the cause, it's genetic and follows a recessive inheritance pattern, meaning both parents need to be carriers, but don't necessarily have the condition.