"Can that pain be a symptom of some illness" should also be accepted as a valid translation of the sentence shown above.
Yeah, for another sentence it said I was wrong when I translated "essa" as this, now it says i'm wrong when I translate it as "that". Make up your mind!
I realize that "could" is technically poderia, but is using it in this instance really wrong?
Not wrong. Could simply makes the question more tentative, less direct.
Why "May that pain..." is wrong?
It should also be accepted.
It's 2021, and "illness" is still not accepted as a valid answer. Ugh!