I'm havin' a hard time tryin' to set up my parker P-38 and when i get it low enough i lose alot of sustain but when its too high it gets uncomfortable and don't like soloing below the 12th fret and on. i can fix my Les Paul no problem but i have a mega hard time with my parker so can anyone help me? and whats with the metal thing at the end of the frets near the 22-1/2" mark.

help would be great
My Gear:
epiphone les paul cusom, Limited edition. evo dimarzio pick ups
Parker P-38
epiphone hummingbird
line 6 flextone
crate vtx 120

head full of ideas.