Sporadic Fever-like Symptoms

So I've had this issue for a little while now but I've never known what it is. Whenever I do any physical activity while wearing jeans, jacket or something which isn't suitable for the activity, I end up with the feeling of having a fever and get very itchy, especially all over my back. I sweat while this happens but I sweat a fair amount in general. This also happens sometimes while in the shower or even if I simply find myself anxious or nervous in an everyday environment, my temperature feels like it builds up very, very quickly and I get very uncomfortable. I've found the easiest way to fix this is to usually take off my shirt or jeans depending on if it's my legs or chest which is itchy. I get this issue even if I'm outside on a winter night when it is very cold.
I've found these links though some symptoms seem fairly different:
https://www.steadyhealth.com/Severe_itching_after_showering_t77599.html?page=3
http://en.wikipedia.org/wiki/Aquagenic_pruritus
 I'm 18, am around 5 and a half feet tall and weigh around 65kg, if this helps.