Q. Shiba Inu. He periodically shakes and trembles, usually unrpovoked and seeming for no reason. Usually cuddling helps but not always. Becomes reclusive
DR. CHRISTIE LONG, D.V.M., C.V.A.
A. I do find that Shiba Inu's are a really sensitive breed. I think the first thing to rule out is pain. That could be pain from a muscle injury or even gastrointestinal pain. Try to pinpoint whether it occurs after a meal or not. He might be painful due to something going on in his GI tract, and the pain is at its worse after he eats.
I've also seen a lot of small breeds like Shibas get back pain, and shaking can definitely accompany that as well. If you haven't see your vet who can perform a good physical exam and look for any signs of muscular pain along the spine or elsewhere. It's not a bad idea at this point to consider doing some blood work just to screen for any problems that could be affecting organ function, for example.
If he's healthy otherwise, I think it's likely that there's something that's scaring him at home. These things can be really difficult to identify, and you have to be really aware and note exactly when the shaking occurs, how long it lasts, etc, and look for patterns. Dogs can hear things we can't, and he may be hearing things you're missing, and the noise is disturbing to him. Cuddling is a good idea, also working to distract him and desensitize him with toys and treats might help. But like I said above - definitely rule out pain first.