
Why don't you have her hips x-rayed to be sure either way. I have a Rottie x GSD and her hips clicked terribly as she was growing (still do occasionally) I was panic stricken after having recently having a lab with severe hip dysplasia, that I may add had come from good low scoring lines.
Anyway took my girl to an orthopedic vet after another vet thought she had it after trying to flex her hind legs, he x-rayed her hips and said she had beautiful hips definatly no problems so I need never worry. She is now 3 and runs furiously catching her frisbee etc and has never had a problem and I stopped worrying, apparently the clicking is quite common in some dogs and is something to do with the gases in the ligaments and no cause for concern.
Back to your girly, as someone else suggested get a 2nd opinion, she obviously has a problem of some sort at the moment and it is better to find the cause sooner rather than later. Metacam may hide it but it won't give you the reason.