About stretching and cardio

[PitbuII]

I have a question about stretching and cardio, about stretching, I saw that when I get stronger and bigger my mobility really gets weaker, my range of motion gets shorter and all, so what I'm looking for is a stretching routine something like PNF that I can do to increase all of my muscles flexibility and ROM, doesn't have to be PNF just read it is good.
Besides that I heard there are different kind of stretching that should be done at different times, so what kind of stretching should I do before a weight lifting workout, after and a one to increase flexibility as mentioned before.
Question two is about cardio, since I started bulking I really stopped doing any kind of it and I really want to have a good heart endurance, like to be able to do things for long times besides strength because I think it's important as well, so if I will run 3 days a week on rest days or in weight lifting days but with a long break between them and I will add the calories I burn during the cardio can I add the cardio?
And if you guys have any good running routine to increase endurance and all that you can mix with weight lifting.
Sorry for bad english, not my first language, thanks in advance.