This is a huge fear of many with HA. Problems with the throat, perceptions of problems with swallowing, burping, tightness in the throat, dryness of mouth, speech issues, slurring of speech, clearing of throat etc are all possible complications of anxiety. Once we begin to fixate on an area a couple things happen. One is things we did naturally like speak or swallow become a problem...as we used to do these things unaware. Now we have taken conscious control over automatic mechanisms and problems begin to arise. Second is we notice things we didn't notice before like hissing S's, or articulation of certain words.
Clearing of the throat is almost always caused by one of three things...laryngophargeal reflux (very common in the anxious), post nasal drip, or just nervous habit.
Now, lets talk about your age group...22 yo would be an extremely unlikely age group to get the regular onset let alone a rarer onset. I would guess somewhere in the neighborhood of 1 in 10 million.
If you can say British Constitution and Pink Elephant...move your tongue around your teeth and tent your cheeks with your tongue you just passed a neurological exam for the mouth.
Twitching is very common in the anxious. I twitch almost everywhere including my neck...had a nasty one last night as a matter of fact.
By all accounts this is likely anxiety with possibly some post nasal drip or reflux. I suspect your barium swallow will come back just fine...and then you need to put this one to rest.
Sounds like you had an EMG, passed then began to doubt the test. That is what we do. Brother, life is too short to worry about worst case scenerios. This worry you got is a real beast...worst than many of the HA worries. You need to do what you need to do to get a grip on it before it eats you up.