Either end of shinbone hurting (4)

I believe the answer is:

sore

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'hurting' is the definition.
(synonyms)

'either end of shinbone' is the wordplay.
'either' becomes 'sor' (I can't justify this - if you can you should give a lot more credence to this answer).
'end of' suggests the final letters.
The last letter of 'shinbone' is 'e'.
'sor'+'e'='SORE'

Can you help me to learn more?

(Other definitions for sore that I've seen before include "Hard" , "Painful spot" , "very much" , "Wound; painful" , "Spot of aggravation" .)

I've seen this clue in The Everyman puzzle in The Observer.

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