Hi Shara,
You need to take your cat to a vet immediately for diagnosis and treatment if you haven't already done so. Cats can be remarkably stoic when it comes to pain, but if it is a broken leg she will be feeling the exact same pain that we would as people i.e. it's the same nervous system. It may be a torn ligament or something less serious that she's damaged, but either way it will need appropriate treatment, which will most likely include pain relief.
Good luck,
Zara The Vet
[
www.vetvoice.co.uk]
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www.zarathevet.com]