<b>are we doomed to never fully comprehend and resolve a lot of questions because the construction of our brains makes it impossible to do so.</b>
I would risk answering no to that
Naturally though it depends on the "lot of questions"
Sometimes I think we/I cant figure out a lot of stuff cause we keep
turning them over in our minds (is that the same as our brain?!? close enough I'd say) - i.e. we give the [conscious] mind (far?) too much importance in the scheme of things.
Think of all the discoveries that were made when people had given up on ever finding the solutions/answers. I remember reading something Einstein said along those lines, I think he may even have credited [someone/thing else]. Me, I'm not too well up on my science history but believe there's a bunch of other very famous discoveries/solutions that were found "by accident" or as said when people had either given up or simply given up thinking about the problem. *
Naturally I'm not saying we shouldnt think
So far, I'll just say that "we give the [conscious] mind too much importance in the scheme of things"
* although it's very often like that also with people who want to have kids but are unsuccessful - when they give up "trying" .. eh .. out pops a kid 9 months later. So I guess that's related to being relaxed when trying to find a solution?
EDIT: added [stuff in square brackets]