What are the major informal obstacles students face when they go abroad for a research degree?
It is not going to magically solve your problems. You will undoubtedly face similar issues. People outside often think that Academia is the life of the mind and the ivory tower. It is not. A successful career, including tenure, often depends on how well you interact with your fellow academicians never mind your students. 

Being an introvert can be very difficult. You can take this opportunity to re-invent yourself. You'll never not be an introvert but you can work on skills to minimize its impact on your life and career. Search out some books on the subject (there have been some popular ones published recently like Quiet: The Power of Introverts in a World That Can't Stop Talking). 

Very carefully consider who your advisor will be. You don't need the prima donna, but someone with whom you can work with successfully.

Join Toastmasters or a similar organization where you are now or where you end up. Look for social, cultural, or technical organizations for your interests--and get involved. That may help you find connections and friends who can help you when the going gets tough.

You might also look into counseling, not to become extroverted, but to learn techniques to mitigate your introversion.

On a personal note: go for it! I'm introvert who's fine with friends. I'm a SME (subject matter expert) so knowing my stuff makes it much easier for me to speak up in a meeting, raise my hand in class (when I was in class), and so on. Don't let imposter syndrome get you either.