I have been told that I have Arthritis in my elbow
I kiteboard and surf mostly,
does anyone one else have athritis and is still getting on with it,
what do you do to treat it,
have you modified how you do it.
And what would happen if I just kept taking pain relief, and continued as normal
Greg, the best advice I can give you is to give up kiteboarding imediately. It can only be doing you irreparable harm.
You should really have taken up windsurfing. 
Anyway, since you will probably ignore all my good advice, here's some more.
It might not be arthritis. It could be sore from tendons which attach somewhere near there and are a bit overworked. It gives an effect like tennis elbow.
I got it some years ago and ignored it. It went away the next year.
I don't get why people seek health advise on internet forums. If you have something wrong with your car you take it to the mechanic, your body is not right - do yourself a favor and go see a doctor, that's the best place to start.
I had "arthritis" like symptoms in my back, started with chiro, which did not help so I went to see a back specialisit, turned I had bulged disc pressing on the spine, they recommended physio/pilates, which helped a lot.
