I'm in turmoil as I type this post. I feel so confused, and my conversation with the vets hasn't cleared anything up

I've been worrying about Misty over the last few months. She's always been a head rubber since we first got her, but lately she's been having scratching episodes when she is excited, which go away when she calms down. We've been to the vets and she's been treated for ear infections, and had cream for her jowls in case there was an irritation there too. She's also started whipping round and looking at her rear end, not everyday, just on the odd occasion. She does seem to like to sleep with her head up, especially on my pillow.

We went to the vets tonight as I wanted to talk to them about SM. I had brought it up before with their head vet, but was brushed off. His opinion seemed to be that as there was no treatment for it, why prove a dog has it. He then suggested I keep her ears clean, and trimmed short as it's more likely to be ear problems. Tonight I saw one of the small animal vets and listed her symptoms, and asked what he thought? I basically spilled my guts about how I'm worrying about her, and how I wondered if it could be SM. He said it's a possibility that her symptoms could be SM related, but as there are no treatments for SM, would it be worth putting her through all the tests to find out. He said I need to weigh up the process against how much pain I think she could be in. I asked, is it not worth getting scanned so she could be properly medicated. His response confused me even more. He said it's so hard to balance the meds, and that most of the time the results are not successful.

He sent us home with Metacalm to see how she responds.

I have such a sore head, and none of my worries have went away. Is he telling me there is no point in getting her scanned? Is it because her age? Are her symptoms not severe enough to warrant a scan? What if the Metacalm does work, would he then try and medicate her without any test? Honestly I can hardly think straight. We only have two good vet practices in our area, but should I seek another vets opinion? Would that affect out pet insurance if we do need an MRI scan?