Lower back pain (7)
I believe the answer is:
lumbago
'lower back pain' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lumbago that I've seen before include "Painful condition" , "Form of backache" , "Rheumatism of lower back" , "Rheumatic pain in muscles of lower back" , "Pain -- a bum log (anag)" .)