Misfortune to remove lock? (8)
I believe the answer is:
distress
'misfortune' is the definition.
(distress is a kind of misfortune)
'remove lock?' is the wordplay.
'remove' becomes 'dis' (I am not sure about this - if you are sure you should believe this answer much more).
'lock?' becomes 'tress' (both can mean a piece of hair).
'dis'+'tress'='DISTRESS'
'to' acts as a link.
(Other definitions for distress that I've seen before include "Extreme anxiety or sorrow" , "Cause mental pain" , "State of suffering" , "Pain, trouble or sorrow" , "Sadden" .)