Painful Itching in winter. Or anything!

Hello, I am a 20 year old boy. And i have this itching problem that occurs in winter time ONLY since 5 years. Whenever i go out in sun suddenly all my body starts itching and everytime in winter when i am about to do a activity my skin starts to itch very painfully, its mostly all over my neck, hands,chest, head. It is really really painful, it feels like someone is poking me with thousands of needles all over my body. And now i have started feeling that the itching attack creates small little pimple looking things on hands chest with red neck. Lately i noticed it starts even if i m sitting in a classroom. For example when i get confused, or nervous of something my body start heating up and it creates the itch, usually it goes away after couple mins when i cool down. Any kind of help would be greatly appreciated. Even a name of a medicine or cream or anything