Answer:
Sam where do u want to be in five years?
This question is grammatically correct.
Even if a comma is placed after the word Sam, it is correct.
Step-by-step explanation:
This happens totally based on how we pronounce the sentence or depends totally on the throw of the sentence. For example, if we say the sentence without pausing, then the need of a comma is absent. But again if we pause after saying Sam and continue, then the comma needs to be inserted. In both the cases, the question will be grammatically correct.