Background:
I had this problem before whit a crucial dreagon.
It was when i tryed to catch the dreagon in the castle. to fix the problem, i was needed to call the dreagon, as soon as he was there, i needed to run away, back in the city. and make alduin leave. then deselect, and select the mission, and run back to the catching place in the castle, call the dreaong again, and then he lost health.

Now, in this map i can't run in to a building. the big building in the map there needs a key, I can run far enough away to make alduin not tagert me, but then i am still not allowed to do a fast travel or something like that. and when i come back, and he targets me again, he will not lose heatlh again

please help me, because i am stuck on this stupid land

This is a major spoiler, wrong place for it.

Guess time.