
Thanks for the response :-) It's a possibility I guess, though I'm pretty sure he hasn't been stung. He was barking completely normal one second, then yelping the next. I was with him in the garden the whole time.
I've had a Google and it's come up with neck pain caused by a disc problem as one possible reason (the neck is held higher when barking). I have actually thought for quite a while that he's got something wrong with his back. We saw a specialist 18 months ago who detected lower back pain but he thought that it was connected to the leg having been carried awkwardly due to a torn cruciate ligament in the knee. He then had surgery for the knee 8 months ago and they decided not to MRI scan his spine as they were sure it was all down to the knee problem. No major issues since. But then about a month ago he was totally unable to sit and eventually got into a down but then couldn't get up at all and my friend had to carry him into the vets screaming. They thought he had a soft tissue injury in his back or hip but after an injection and some metacam in his food he seemed to get over it in just a few days (was up and walking that same evening) and he's been back on normal walks for about 2 weeks now.
He seems normal in every other way - moving fine etc, it's just the yelping when he barks. Very odd. We have an appointment at the vets tomorrow so will see what they say.