I Am Embarrassed to Show Emotions

I don't know if it's exactly embarrassment, I feel that too, but also fear of exposing myself so much or fear of getting misunderstood (because I can never find the correct words).
It's kinda contradictory that I believe in human communication, because it can only be achieved by expressing our thoughts and emotions, something that I refuse to do.
Someone told me yesterday to just say what's on my mind without caring about what others will think, they might accept it or not but they're the ones responsible for that. He said if they won't accept it I will find a way to deal with it afterwards. I think I might start doing that eventually, to some degree.