A kid on medication, powerless and uncomfortable (3,2,4)
I believe the answer is:
ill at ease
'uncomfortable' is the definition.
(I've seen this before)
'a kid on medication' is the wordplay.
'a kid' becomes 'tease' (I've seen this before).
'on' says to put letters next to each other.
'medication' becomes 'illa' (I can't explain this - if you can you should believe this answer much more).
'tease' after 'illa' is 'ILL AT EASE'.
'powerless and' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
(Other definitions for ill at ease that I've seen before include "Nervous, uncomfortable" , "Fidgety" , "awkward" , "Unable to relax" , "wound up" .)