Head examiner a learner probes whichever way (7)
I believe the answer is:
analyst
'head examiner' is the definition.
(a psychoanalyst examines your head)
'a learner probes whichever way' is the wordplay.
'learner' becomes 'l' (as in a learner driver with L-plates on their car).
'probes' is an insertion indicator (probe can mean to poke or prod into).
'whichever' becomes 'any' (I've seen this before).
'way' becomes 'st' (abbreviation for street).
'a'+'l'='al'
'al' placed inside 'any' is 'analy'.
'analy'+'st'='ANALYST'
(Other definitions for analyst that I've seen before include "One examines the elements of something" , "Practical chemist" , "Chemical researcher" , "One with detailed understanding (of psyche or systems)" , "Person who interprets system structures" .)