Should freedom of speech allow a person to say anything they want whenever/wherever? Should there ever be limitations? If so, when?

I prefer freedom to express an opinion.

No, because that's not the definition of freedom of speech. It is about having the freedom to express your opinions in public without being censored or arrested for expressing your opinion.  "In public" being the key part. For example, you can't, and shouldn't be able to come into my private property and disrupt my private gathering to voice your political opinions. You can, however, voice them in the public space in front of my property whenever you want, but you can't do it however you want.

Riot King is on the right track. You can utter hate speech, like "Green people are no damned good." When you tell people to kill them, you've stepped over the line. Even "There are good people on both sides" is protected speech. Stupid, bigoted, but protected.

All Constitutional Rights come with limitations.  Those limitations are well-documented in law and available via Google search. 

There already is, go to the airport and tell TSA there is a bomb in your luggage and see what happens 

Anything except when causing people to panic or causing them to riot.