It is the new "bad" thing and thus gets a lot of press lately but it is also probably true that you have hear many complaints, you just may not have associated them.
A sore throat, is caused by inflammation of the mucus tissues in your throat, for example. A mosquito bite itches due to inflammation, it is the immune response to the mosquito's saliva that you feel as an itching sensation.
The 'new' thing however is that this mechanism can occur pretty much in every cell of your body and some people have speculated it is the root of a number of ailments. Google 'inflammation' on scholar.google.com and you will find a number of papers discussing different ways that it can affect you.