When i do any small activity, i feel like thorns are pricking my skin especially in the winter. i have this for some years now but it's getting worse!

May be miliaria: May be a form of miliara (heat rash). A primary care doctor or dermatologist may help prevent and treat the symptoms. Keeping the skin surface smooth, soft, intact and healthy is important, so try to avoid over-scratching. What happens during exercise (when you start to sweat) is that the sweat glands are blocked at first (causing symptoms), but once sweat is able to flow freely, it feels better.