Aww poor Bruno, so sorry you're going through this with him. Did he jump off the couch or bed and maybe strained his leg? He may have sprained it. The vet didn't find anything wrong, so I would continue to keep an eye on him, give him his meds, and try to keep him as quiet as possible to rest his leg. When Dozer was a little pup, he fell on his paw and he sprained or bruised it. The vet checked him out, and took X-rays, but also didn't find anything wrong, Dozer was favouring his foot and would not walk on it, and he helped when ever we moved him. It was awful to hear him cry. The vet gave him pain medication and an anti inflammatory, we put him on a dog pillow on our bed to sleep, and we carried him up and down the stairs to go outside. During the day we had to crate him so he wouldn't try and walk on his foot. It took 4 days before he would put any weight on his paw, or try to walk on it, then he started to walk on it,but was limping. It took about a week before he walked normal on it. Bruno should be okay in a few days, and if you don't see any improvement in 3 or 4 days, have the vet recheck him, but it does take a few days for it to heal. I hope he feels better soon. Please keep us posted on how he's doing.