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If the cat is not painful...if the tail is twitching..this may be normal for a cat. If the cat is crying or painful...then a diagnosis needs to be reached...but cats do tend to have muscle type twitching down their back, hind quarters and tail...and it is normal.
I will be honest...your vet would need to see an example or video of what your cat is doing to tell you if this is the normal twitches cats do. My instinct is if the cat is not manifesting any other problems OR painful...I think she is probably normal.
I hope you can see a vet for her shots sometime soon. Good luck, and any changes with her walking, dizziness or mood changes...you need to go to a vet.