Large dog having neck pain

[LaurenBev]

Hi, My 95 lb bluetick coonhound Leo seems to be in pain. He got up and shook his head around, like he does every morning, and yelped and cried in pain. I've checked his ears and he lets me pull and move them around, without any protest. So, we think its his neck. He's currently sitting completely still, trembling, won't eat. We've called the vet, we're going in for a visit in a few hours. Any insights on what it might be? And how we can make him more comfortable in the meantime? He's currently sitting under the kitchen table... my poor big baby, I hate to see him in pain.

Leo's stats: he is older, although we don't really know precisely how old. Vet estimates him at around 8 or 9? We rescued him about 3 years ago, and we don't really know anything about this 'former life'. Also, he's a touch overweight, maybe 10 lbs.

Any advice is appreciated.
Thanks, Lauren