Just popping this in here for now, as a place to begin:

If you suffer from, or live with/love/care about someone who suffers from, Cluster Headaches,
 this is THE place for you!
http://www.clusterheadaches.com/newvisitors.html

I subscribe to the weekly e-alerts on the site below, so I put cluster headaches in the search box
 & got about 40+ somewhat related articles. 
There are also many articles relating to arthritis
Somewhere there - is also a forums link
http://www.hsibaltimore.com/hsiindex.shtml

 

Extensive coverage & treatment possibilites.  Also has tons of topics and information

 

Information including a list of specialists on the net

 

I'm including this link as I like the way information is provided & Both my son & I had excellent
results when treated by Dr. T.        

 

 

Extensive information about Osteopathy UK & US
http://vzone.virgin.net/big.phil/index1.htm