Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
I suspect that Lucy is starting to have some arthritis issues or an unstable disc in her back that causes pain so she does not want to jump up.
This is very common in this breed because of their conformation. Since Lucy does not have any digestive issues, this is the most likely cause for this pain. Since this is deep within the vertebrae, she will not show pain when you touch or palpate these areas. This can happen when Lucy jumps up or down on something or just moves the wrong way.The best thing you can do for now as long as Lucy is eating well now, is to give her aspirin at 5 mg per pound every 12 hrs. This will decrease the inflammation that is causing this pain and start to stabilize this disc. Do not allow her to jump on or off anything or even climb stairs to allow this disc to stabilize.It is best to have your vet examine Lucy to be sure that this is the case and that this treatment is appropriate.
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, ***** *****
Thank you so much, Lorraine, for your kind rating. It is very much appreciated! Even though you have rated, we can still communicate. If you have other questions, please Reply. I am always happy to help. I hope Lucy feel better soon!
Have a wonderful day!