The phrase "What are you doing ___?" means "Why are you ___?". It also expresses a feeling of surprise, and sometimes accusation:

“What are you doing here?”

What are you doing calling my house in the middle of the night like this?

You can see from the examples above that "What are you doing" can be followed by a word like "here". It can also be followed by "there", a prepositional phrase like "on the roof", and so on. Or, like in the example at top, it can be used with "___ing":

What the hell are you doing calling my wife?