Answer

Hello. I'm glad you checked her ears. I do think the vet should do another exam deep into her ears where he or she can light and magnify into the canal. You can also try flushing them out but that is mostly for cleaning debris (it can't hurt.) If you don't have ear cleaning solution handy, you can use 1/2 vinegar and 1/2 water solution. Don't use a q-tip but just a cotton ball to clean out the debris that you can actually see. Also, there are several reasons for shaking or trembling. Some reasons are caused by fear, nervous energy, sensitivity to cold, or even anticipation of certain activities. (Many of the same things that can cause people anxiety or to shiver from fear or cold.) Another common reason for dogs to shiver (especially the smaller breeds) can be due to being in pain.
The only other thing I can think of is more X-Rays especially if they X-rays were done only around her head/neck area. It could be her leg(s) or lower back. If your vet can't give you an answer, you may think about asking for a referral to a specialist. I wish I could give you more information but without seeing her, it is difficult to pin point.Keep in mind that this could be something as minor as a pulled muscle or a sore back in which it should heal itself. (She would probably be holding her head down low if it is her back.)
I will be thinking about your little one and hoping she is okay. I would love if you could let me know how it turns out. If I think of anything else I will let you know.