Introversion is one of the most misunderstood concepts in Psychology. What it means is that your brain doesn't need so much stimulation to get going. You can create your own inner world.
Because of this being around other people can overstimulate an Introvert to feeling overwhelmed.
Extroverts need other people around them to kick start their brain. They feel under stimulated and so uncomfortable without being around people.
Having spent years studying happiness and writing a book, 'The 32 Building Blocks of Happiness'.
I have come up with a definition of happiness.
It's the freedom to be yourself fully, plus a focus on something greater than your sense of self.
This is where the increased self-consciousness of an Introvert can inhibit happiness by preventing yourself fully being yourself. And also by being a little self-obsessed (for lack of a better word).
So the problem becomes a bigger deal, in your mind, than it really is. And because you focus on that, your sense of perspective shrinks and your world becomes smaller. Therefore it becomes an even bigger deal and you feel stuck.
Where Introversion helps,is that you usually have a clearer sense of self. What you're about?
What cause do you really care about?
What's your mission in life?
You have to use that insight and be brave enough to share and express that with the world. In that expression, your focus goes out beyond yourself and you grow as a person. In that growth comes the solution to your problems. Of course, the problems also seem diminished because they occupy less of your thoughts relatively.
I hope this helps.
Best of luck,