here’s a few theories i have based on experience. i’ll fully explain them if the interest is there. if it isn’t then i wont be wasting my time 
i just hope that none of these are actually true…thatd be embarassing…
I believe that #1 and #3 have already been proven. I don’t know about #2 though.
#2 sounds possible, I’m no expert on the brain, so who knows?
Shyness is the result of your upbringing. Everything that happens to you when you’re young shapes you in some way. If you want to call this a disorder, go right ahead – it certainly feels like one to me. 
I personally think mood is determined by levels of certain chemicals, rather than brainwave activity. These chemicals affect the way the brain works. Some of them prevent rational thought (rage, anger) and others encourage more friendly behavior.
Often when people don’t remember dreams, it’s because they don’t awaken from a REM period. However, it is still possible to recall dreams even if you don’t wake up directly from REM sleep. Equally, it’s possible that someone might still fail to recall any dreams despite waking directly from one. If you don’t put any effort into remembering them, you won’t remember them. 
well i think shyness is a disorder due to the fact that people that are really hyper and stuff have a disorder so thats at one end of the spectrum so i thought shyness would be at the other. plus its just isn’t normal. like some days i’m shy, and some days, like today, i’m upbeat. so therefore i thought mood was related to brain waves due to the fact that when i was listening to this certain song, i became happier and more upbeat. sound waves can alter brain waves quite a bit, so thats why i thought that. i guess that since everyones brain waves are different a song that correlates with that pattern will be in sync with the brain waves of a good mood and therefore when that song is played a good mood will endue. i think that dream thing is true though…
Shyness comes when you don’t want that other people think your an idiot, or you think that your not good enough for something, you want to improve or keep your image and that way your ego as it is, I think it’s not a disorder because I believe everyone has been shy even once in a lifetime.
Just a thought.
I watched a show about human instincts and it said that in the early stages of development people lived in small groups. I guess everyone knew each other like family and they wouldn’t meet new people. I think that people would be shy because they know when they meet someone new or do something that could potentially be embarrising that if it goes bad it would harm their reputation. This isn’t very desirable in small groups. (who do you turn to if everyone in that small group doensn’t like you).
These days there is not really any need for shyness infront of people you’ll never see again, but even so, people can be shy.
To sum up, i think shyness had developed as an instinct.
Hmm…I am one of those plauged by the disorder of shyness. Calling it a disorder describes it well. But I think there are different variations of shyness. For me, sometimes it’s like the inability to turn your inner thoughts into spoken words in order to express them with others or the inability to change your feelings of something into action. I often am thrown into a state of frustration whenever I am trying to explain to someone my ideas or opinions. I think it’s because I have so much I’d like to say to that person, but I can’t get get the right words to express what I have to say. Whenever I do actually try and explain something, it comes out in a huge wreak of words that don’t make sense or don’t express what I had to say. So, in fear of this happening, I usually don’t say anything at all. The other, more simple, part of being shy is just the fear of rejection. It’s like an overactive defense mechanism we have in order to pretect our feelings, turning off only when you’re around someone you’re familiar with, or that you don’t care to be shunned by.
Oh! And someone mentioned how youre raised greatly affects this. I also agree with that. If a kid lives in a home where the family isnt that social or interactive, then yeah, they have a greater chance of being shy later on in life. The level of interactivity you have with other kids when youre young also affects it. If you were an only child who didn’t get that much interaction with kids when you were growing up, you don’t really have a change to develop good social skills- I beleive that’s the case with me. So uh, I’d said there were 2 variations of it…but let me take that back. It can exist in all degress and can comeabout by all different kinds of events and lifestyles.
…but all this I’ve said now I’ve never actually thought about, and it all came together right at this moment…That’s just my say on things, I may be totally wrong…or what I’ve typed may make absoulutely NO sense…but eh, it happens.
Yeah, I agree. I’m also shy, especially around people I know. Which is weird, because it usually works the other way. I’ve always been known as really quiet, I don’t know why I don’t talk. I was thinking on this the other day, and I thought that maybe it was simply that I don’t have anything to say. But I don’t really like that idea. People have known me as shy for so long that it’s become embarrasing to speak because they turn around and stare at me. I think that may be half the problem. Next year, I’m going to a school where I don’t know anyone, so I’m going to start fresh and talk as much as I can. It might work … 
Once again, I agree with Atheist’s post on this topic completely. I will only append: while it is accepted by some that chemical balance is the cause of “mood” (a long-term emotion), and emotion may be the effect of these chemical balances on the body-image of the person, the actual process of the correlation between the chemicals and the changes of emotions are still very disputable.
I can definitely see how shyness could be a disorder. Quite an irritating one really. Like Imagine said, I don’t talk alot either so when I do everyone looks at me like I’m supposed to say something important to make up for it. 
I think it’s something like a blockage, like a wall between your thoughts and the words that are supposed to come out. I know it has something to do with genetics, although I’m not sure how big of a part that plays in it.
I always thought of shyness as something developed through your lifetime, depending on the way people react to what you say or do. But then again, looking at it from another point of view, there very young shy people that haven’t had experiences like that. And a lot of other things would disprove my way of thinking. Hmmmmm. 