What Causes Involuntary "blushing" With Face Heat, Redness, Burning And Throbbing?

Ever since fall I've been blushing randomly and in front of certain people. I'll think "I hope I don't blush" and it's like lighting a match my face gets really hot and burns and sometimes throbs. Being ginger it's my entire face that gets red, not just my cheeks so it's really embarrassing. But it seems like it's gotten worse now and it happens more frequently. I can be shy when I'm with a group of people I don't know but in general I'm not shy. Why do I keep turning red?