This could be HOD or panosteitis.
You can read about owner experiences with this here
http://www.bmdca.org/health/Orthopedics/Panosteitis_and_HOD.php
You should have your vet check the dog in case there is an injury.
He could also have a congenital or hereditary elbow problem or an injury to the elbow and you should have that checked. You can read about elbow disease here
www.acay.com.au/~dissi/elbow.htm
I'd say before doing any home treatment x-rays and a vet exam to figure out just what is sore is what you need to do.
Hope this helps you!
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