I think you are
a human heart
I am seen in darkness and in light
In light during an operation. Darkness via one of those machines which hospitals have.
I am calm yet tend to fright.
Explanatory.
I can be quiet, I can be loud.
When you're scared your heart beats louder.
I hide in shame, yet am so proud.
It's common saying that your heart feels (technically it doesn't but still). At times you feel good about yourself and at times the it's the other way around.
I can be different, but still the same,
Different health conditions but same functionality.
I am straightforward yet am playing games.
Nothing solid but here goes. Your heart wants to do things that are fun and wants to avoid work?
you can easily find me,
You just have to look within. (probably finding what you love)
but you'd have to look and see.
You have to look within :)
I am found every where I know,
Hearts are pretty common. Might also be referring to love :)
but why is it sometimes not so?
People being greedy, cruel or mean?
so many things that I can make,
If you're heart is set to something, you can do so many wonderful things.
but how many tries will it take?
Not quitting and sticking to your goal.