is it common to have 1 arrow that u jus cant get a bh to fly right with it?

Common, no.

Does it happen sometimes for various reasons, yes.

Yea,somtimes it is.TRy it with a broadhead that flies true on a different arrow,if that arrow flies true it's the arrow.If it does not it is probably the broadhead.I had one arrow once that you could see it almost loop,on futher inspection of te broadhead I discovered a bent blade.

ive rotated the nock all three ways... ive changed nocks... i changed broadhead.. done jus about everything but re fletch....jus wont fly right

Try squaring off the face of the insert with a G5 A.S.D or something similar.

Does it fly right with field points?

yeah it flys right with fp.....