What Causes Pinching Feeling And Pimples On Skin?

whenever i just run for half more than 1 minute or get nervous to any situation or feels like sun is on me and i am getting sunlight or just i got a thought that i am being most observed in party i just start feeling like pinching in skin with burns and full skin gets red with big pimples like things. Head starts paining with unconsciousness and stomach start acting as having acid in it and feel like vomiting.

I usually take allegra 180 mg which controls the situation a bit but completely gets fine after 2-3 days. In-between if i pour cold water on head, it feels good.

Please advice what it is and how can i overcome this serious problem lasting since 3-4 years.