What exactly does the 1st Amendment DO?

Thoughts on the mind today having me wondering what exactly is the point of the first amendment. Referencing this in my mind is the freedom to speech. Is it simply a right to say anything you want at any time to any person. What exactly is protected. It has me thinking because of reading that Prof Daly is being investigated. Does the freedom of speech have any conditions on it. My first thought is "No." Freedom of speech is exactly that, the freedom to say whatever you want with no conditions on it. Then i thought about it more completely and i realized that all the time we are kept from saying anything we want. You can't shout "fire" in a crowded theater for no reason. You can't lie under oath. You can't use hate speech because thats a crime. You can't use certain profane words on television. Everyday we are "protected" from hearing things that are deemed harmful for one reason or another. So we really don't have a complete freedom of speech. Does this mean that the government should have the right to regulate what is said about other things as well? Where does its influence on speech end. There was lawsuits against the Swift Boat Veterans because people accused their accusations of being lies. Does it matter who's speech is protected? Is CBS protected by the 1st amendment if they want to air documents that have been proved to be almost certainly false? Can a member of Congress say things that are completely untrue or harmful if it helps their position? All of this is on my mind today and I don't really know what to think. Is speaking that there are massive atrocities being committed by troops when its untrue treason? I would say that intent has alot to do but it seems like a double standard, occasionally political but oftentimes not, is going on with the government and it seems quite unfair to me.