In this context it means "as well as " Or "And also is"

It means: so is the question... or the same is the question ....in other words it is difficult to answer as well... :)

I agree. It's similar to: 'I think English is difficult' "I think so too" :)

It is a way of repeating "difficult to answer": The second sentence means: "The question 'how do we achieve it!' is also difficult to answer." I don't know why the question ends with an exclamation mark.