I want to bulk up big time and i know how to i have done it before but got hurt so i couldn't lift and never picked it back up...entered freshman year of hs at 125 left at end of sophomore year 170 but my question is what can i do to keep my flexibility when bulking up...just stretch alot? I would always stretch b4 and after working out and didn't get too tight.

Bulk and dexterity are at different ends of the spectrum. You can look at at gymnast do, cuz they tend to have both. One exercise I like is handstands. Gives you a triangle back, broad shoulders, upperbody weight,and hand strength to swing the bat. Limited dexterity lost.