It depends on what you mean by “shyness”.
Current research into temperament suggests that some people are naturally more hesitant to meeting new people, and some are naturally more inclined to enjoy spending time alone. Some person are neither, some are both. However, these inclinations need not to lead into the person not being “social”, either in the meaning of able to enjoy the company of others, or unskilled in understanding social cues and situations, or insecure. The opposite of the first type of “shy” is not “social”, it is “not very shy”. The opposite of the second type of “shy” is not “social” either, it is “someone who cannot enjoy being alone as well”.
However, often in our culture people whose natural tendency is to take their time when meeting new people are labeled “insecure”, or called “shy” as if that is a bad thing. That in itself can lead to the kind of “shyness” that can be a real handicap: being so uncertain of yourself in social situations that you cannot manage in them. This easily happens if well-meaning people try to “encourage” the shy person to interact faster than he or she is personally willing to, instead of letting him/her take work the situation in his/her own pace.
Other causes of such insecurities usually relate to bad experiences in the past. Even a person who is naturally inclined to very little hesitation about new people can develop such a hesitation if his/her experience suggests that strangers are usually hostile, and a person who would actually strongly prefer company to being alone can isolate themselves if they have many experiences of rejection.
So, it is important to be very specific when you say “shy”: natural normal tendencies, nervousness about not living up to the social expectation of everyone being outgoing, or actual debilitating insecurities/traumas. Not all shyness is trauma or a bad thing! In fact, it is perfectly normal to be nervous about meeting people, and especially previously unknown people. Lack of social skills does not correlate to that sort of shy.