What Causes Crawling And Itching Sensation On The Body?

I sit at my computer for many hours each day. I have noticed for sometime now that especially later in the evening, I feel as if there are small pests on my skin, creating a sensation of crawling, biting and itching. In warm weather, I have noticed that the computer screen attracts a variety of flying insects, some very small. I have been told everything from your are going crazy to it s a result of exposure to the radiation coming from the computer. It is now to the point that it is causing me to doubt myself and wonder if it could be a reaction something entirely unrelated, but brought on form the exposure to the computer.. And ideas?