About inclination being a pain (5)
I believe the answer is:
cramp
'a pain' is the definition.
(I have seen 'Muscular pain' mean 'cramp' so perhaps 'pain' could also mean 'cramp')
'about inclination' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa').
'inclination' becomes 'ramp' (an inclined surface).
'c'+'ramp'='CRAMP'
'being' is the link.
(Other definitions for cramp that I've seen before include "Painful muscle problem" , "Confine - muscular spasm" , "common among writers" , "Muscular spasm, very painful" , "restraint" .)