What is wrong with the story missions?
You only get rewards the first time you do a story mission on a particular character. Otherwise we could mine tomes by repeatedly doing the last mission in the level 10 story.
Hm. Was your character eligible to do do the “Distorted Reflection” achievement? For the season 2 missions, you usually have to play through the entire story chapter once before you can earn the achievements. So, if this was that character’s first time going through that chapter of season 2, that’s probably why you didn’t get the achievement and reward.
As for your second question, you only earn that Mastery point (the one for completing the level 30 story) once per account, even if you do the story again on a different race. So (for example), once you’ve done the level 30 story and gotten the Mastery Point for it on a human, you can’t go earn it again by doing the level 30 story on a sylvari.
One Mastery Point is rewarded for each Personal Story Level Arc, regardless of race, per account; thus a total of 8 Mastery Points can be acquired through the Personal Story.
Season Two Story Achievements can only be completed by a character that has completed that Episode previously; in essence, the same character must play the Episode twice.
Good luck.