Ooh. It wasn't down the side of your thumb, was it? Because I have been getting tenosynovitis there since I started canoeing but it didn't hurt worse when I was actually paddling, so the only thing I could think of was it being from lifting boats and putting too much strain on my wrists. And it got worse when the weather got colder. And I have just had a bit of a brainwave that in the cold weather we wear cag tops with watertight seals at the wrists so as not to get soaked all the time with cold water...hmm. And the doctor I talked to wouldn't necessarily know about that in order to suggest it as a cause when I went to see him.