"Why is your neck sore?" Was not accepted. Not sure why?
I think this should be accepted as well.
Please report it, so that they can fix it.
It also said that "Why did your neck sore?" Was accepted.
Hmmm...that's strange, is that (grammatically) correct English ?
You're right about the times/tenses.
Indonesian doesn't use tenses.
It depends on the context.
The context should indicate the time/tense.
Without context, it can be translated into whatever time/tense.
This is also something that needs to be updated in the collection of alternative answers.