I know what you mean in requesting a story? (4,2,5,2)
I believe the answer is:
tell me about it
I believe this clue is a double definition.
'i know what you mean' is the first definition.
(both can be used to show sympathy or agreement)
'requesting a story?' is the second definition.
(a request that someone tell you a story)
'in' acts as a link.
(Other definitions for tell me about it that I've seen before include "it is the usual problem" , "I need to know" , "I want to learn from you about computers and things" .)