We have a pear tree...

Good morning everyone,
(1) we have a fair to middlin' sized pear tree and it is congested with branches reaching up to the sky.  How do I prune it so the same skyward growth doesn't happen next year?

(2)  we have had about a dozen large pears (stop sniggereng in the back row) from it but all from the same smalle area of the tree, you could say from the same vertical branch, does anyone have any idea why?

(3) why when an apple tree next to the pear tree is riddled with brown rot, yet the pears are free of the problem?

Cheers,  Tony.