Friend on facebook just diagnosed with overuse syndrome. In my country we never heard that term. Is that something new?

American lingo. This is not new, but receives more attention because it is occurring more frequently. An old term for overuse syndrome in one's elbow is "tennis elbow.". Or in one's knee "housemaid's knee." carpal tunnel syndrome is an overuse syndrome.
No it is not. Overuse syndrome is a condition where a part of the body is injured by repeatedly overusing or exerting to much strain on that body part. Like carpel tunnel syndrome, tennis elbow. Good luck thank you.