"У вас болить вухо?"

Very poor english translation. It should say , "do you have an earache?" Or " do you have a pain in your ear"

I concur with what has already been stated by the other Duolingo users. In (American) English, we say "Do you have an earache?" OR "Do you have pain in your ear?"

In English it should say "Do you have pain in your ear? " Pain is not treated like a quantity, but rather a quality so it would not get the article a. You would not say I have a pain. One would just say I have pain or I am in pain.

You can say, my boss is a pain, however.