Self-Conscious

What does it mean to be self-conscious? Most people think of being self-conscious as being embarrassed about your appearance or something that you've done. Of course, sometimes that's what being self-conscious is.
But to be self-conscious aren't you aware of yourself in many ways? Isn't it more than just embarrassment? If you break your arm, chances are it hurts badly, and you are quite aware of this pain. Are you not then being self-conscious? Are you not realizing that you are in severe pain?
In fact, people are almost always conscious of themselves, even while sleeping in some cases. If you have a dream that you're involved in, you must somehow be aware of yourself. I've had several dreams where I couldn't walk to class or I knew my dog was in trouble, but I couldn't get to her.
In gym, you're probably aware that you're sweating and thirsty. Seeing as how you're aware of this, you must be self-conscious. If you weren't, would you go and get a drink afterwards?
To be conscious is defined as perceiving, to be aware of surroundings and sensations. You are aware of your thoughts. Obviously, when you know of your thoughts, surroundings and sensations, you must be self-conscious.
It is my belief that the definition of self-conscious has become far too narrow. It's more than just thinking, "Ye gads, I'm fat, really ugly, and my hair's a mess." It's realizing that you're in a severe amount of pain and you feel it, and you come close to wishing you were dead.
So, what is it to be self-conscious? You tell me if you think I'm wrong.