Suggestion of doubt after learner driver gets to talk about old pain in back (7)
I believe the answer is:
lumbago
'pain in back' is the definition.
'lumbago' can be an answer for 'pain' (I've seen this before). I'm not sure about the 'in back' bit.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for lumbago that I've seen before include "Back problem" , "Rheumatic pain in muscles of lower back" , "Rheumatic pain in the small of the back" , "Maul bog badly for a rheumatic affliction" , "Rheumatic backache" .)