Two other things have helped me get over paralyzing "shyness" ... one is medications for social anxiety which help in ways I don't understand... they just gave me the boost to get out there and practice being with people in a way that was not terrifying for me.
The other thing that helped was that I quit calling myself "shy". I prefer to think of myself as "reserved". Shyness connotes fear to me. Shyness means I CAN'T interact with people without wanting to just die inside. Being reserved means I CAN interact with people on my own terms... in a quiet, comfortable mode. Being comfortable in my own skin in the presence of other humans did not happen overnight.... but changing how I perceived myself certainly helped get me going in the right direction. When I slip and start getting anxious again... I find it very soothing to remind myself that I am reserved and that is just fine. I can socialize in a manner that suits me and feel confident doing it. The more I do it. The more confident I get. The easier it is.....
Being shy can be a curse. It can be so isolating and confidence destroying; speaking as a former (sometimes current) shy person. For me, I was lucky enough to have a job early on that forced me out of my shyness. I enjoy having "real" conversations with people so as terrifying as it was it was still a gift. I still have to push myself in many situations to not be shy and sometimes I fail. Some other situations I feel more confident and I don't even think about my shyness any more.
As with anything you are anxious about the more you expose yourself to what you fear the easier it becomes. Also, the more you avoid it the more it reinforces the fear.
It sounds like shyness has taken a lot from you Pete. Perhaps it's time you stop letting it take from you? How can you fight back now? No excuses either!
How has it affected my life? It's been a curse, a barrier, a constant sapping of my self-respect. It's been at the root of my difficulties with loving myself, and my feelings of inferiority. It makes me feel cut off, substandard, and has led me to be secretive, dishonest, self-absorbed in a shut-in, circular kind of a way.
Have I challenged it? Barely. It's so much a bedrock of who I am, I can't conceive of living life as a man devoid of shyness. I don't know how people do it.
I blame my shyness, and thus my very nature, for my lack of achievement, all my regrets and failures, my dearth of friends ... you name it.