"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances."
- First Amendment, U.S. Constitution
The trumpkins and others seem to be making a great deal of noise about the Trump Rally shut down the evening of the 11th (last night, to me) in Chicago - idiots on both sides are crying out "First Amendment! First Amendment!"
They are idiots, all of them.
The First Amendment (and courtesy of the 14th Amendment and SCOTUS, all lesser political bodies) prohibits Congress from (among other things) abridging freedom of speech.
It does not shield speech from the actions or words of our fellow citizens or private organizations thereof - there are other laws relevant to such things, but by the time those are up for discussion the 1st Amendment is clean off the table.
Did a government or government agent try to censor or suppress your speech (aka freedom of expression)? If not, you do not have a "speech" case under the 1st Amendment.
So what about those other areas of law?
If some large lunged type follows you about screaming "OOOK! OOOK! OOOK!" every time you try to speak, you probably - depending on local law - have a case for harassment, and maybe to question their sanity in front of a judge.. Not a First Amendment issue.
If you show up in someones living room at two in the morning and start belting out "Eskimo Nell" at the top of your lungs you are not exercising freedom of speech. You are exercising breaking and entering, trespass, possibly burglary and being a bloody nuisance - the homeowner with a shotgun and members of and the local law enforcement agency will have things to discuss with you. None of your actions here are protected by the 1st Amendment.
If someone puts on a large public event and wishes to exclude a person or class thereof, they can. They are exercising their 1st Amendment rights to control their message.
Finally, if you go spelunking in bears dens and get mauled after poking the bear with a sharp stick - play stupid games, win stupid prizes. Still not a First Amendment issue.