If we are talking about modern day/Christian ideals of humility then yes that is forced. Thor is so confident at times one would call him arrogant, but there is a fine line between arrogance and self-confidence. Namely, with Thor it tends not to be arrogant because he is not throwing it in everyone's face all the time and can back up what he says.
I do however agree some humility can be part of a god. Odin wanted Thor to learn humility because there are consequences to his actions. A god has to be humble enough to know there limits and that they cannot always have things their own way especially when clashing with the king of the gods. They also have to know that as a god they have greater responsibilities then their own wants. Thor needed to learn all of these lessons.