behind, back, later
後 centers on the idea of being spatially or temporally behind: the back side, what comes later, or what follows after.
after
behind; rear
later; afterwards
end; conclusion
from now on; hereafter
back; behind; rear
afternoon; p.m.
second half; latter half
front and rear; front and back; before and behind; back and forth
regret; repentance; remorse
immediately following
postwar period; period after Second World War
junior (at work, school, etc.); younger people; younger student
the latter; the second
in the future; another day; later
rear; back; behind
succession
back; rear
latter period; second half; late stage; third trimester; second semester
after death
after this; from now on; hereafter
retreat; falling back; moving backwards; reversing; backing up (of a vehicle); retrogression; retraction
after school (at the end of the day)
posterity; future generations; future life
後 combines 彳 (movement) with a phonetic component that also suggests delay or following. The modern form is simplified, and the exact historical development of the right side is uncertain.
The left side 彳 suggests movement, and the right side looks like a trailing thread 幺 with a foot 夂 lagging behind. Picture someone walking while a loose thread drags behind them: that trailing thread is always behind.
For ゴ, imagine a person walking and a ghost (ゴースト) follows behind them: ghost -> ゴ, always lagging behind.