Student or Learner
I'll go after you/I'll go behind you.
--- Do they mean the same thing?
Hi, I am not a teacher, thats only my opinion.
Go after you means that the person will follow the other one, wherever he may go.
It may also mean that other will go/leave after the first one leaves.
Go behind, or rather walk behind, means that he will be walking at the back of the other person.
A teacher would surely help you in a better way.