Good Morning and welcome. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I am so sorry that Spider is uncomfortable by this...
This is caused either by an ear infection or by something in her ear such as a foreign body or a tick. Even with an infection, you may not see any discharge because the ear canal is very long and the infection may be deep inside.
they will do this shaking also due to allergies that are bothering Spider.
the best thing to do first is to apply Swimmer'a Ear to the ears every 8 hrs. This can be purchased over the counter at the chemist and will dry out the ear so bacteria cannot grow. Massage this down and then wipe the excess with a kleenex.
If this is caused by allergies, it will help to give Spider benadryl or Diphenhydramine at 1 mg per pound every 12 hrs. This can be purchased at the chemist over the counter in the infant liquid form and is very effective against allergies.
If this is not enough, then your vet will have to examine Spider with an Otoscope that can see deep within the ear to remove a foreign body or determine the cause for Spider's discomfort.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please Reply so I can clarify for you
Sincerely, Dr. Loretta