Pain when swallowing can have several causes. One of them is swallen lymph nodes in the neck (which you can usually feel from the outside as well). This is actually not a really bad sign, in basically means your immune system is working hard clearing out whatever is ailing you.
Another common cause is simply infection in the throat itself, which you can usually see looking down your mouth (tissue is more red than usual, often swallen etc).
As far as temperature fluctuations etc go: they have nothing to do with catching the common cold or even influenza directly. Being in the cold does not make you more suceptible, and can never be the root cause of any infection.
What DOES make colds and such more prevalent in winter is how we act in cold weather: we stay indoors more, ventilate less etc. This makes it easier for virusses and bacteria to spread between people, causing outbreaks to often occur in the cold season.
Outbreaks of the common cold also occur in warm places, especially those that are warm enough to drive people inside air conditioned spaces resulting in the same problem. One way to get the common cold is by international air travel: you will be in a confined space with people from all over the world having variants of virusses you have no immunity too. Usually it's no big deal, but just watch how often you'll feel a bit ill about a week after such flights.
