I don’t find a point in going around in circles. Have you found a source that:
1. Emotional Tzaar isn’t Tzaar. and
2. Tzaar has to be that strong that he will not be able to do the act.
The fact that you continue to ask these questions show that you continue to miss the point.
The answer to those two questions is: who cares? I’ll grant you both (although the first is debatable) but that doesn’t address the point.
Now please answer my questions:
1) Don’t you think there’s something wrong with a version of Yiddishkeit which causes one to be unable to do a mitzvah?
2) Why do all the Lubavichers not sleep in the succah when probably none of them actually feel this tza’ar?