Good Morning and welcome to Just answer. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
These symptoms could be due to a Luxated Patella. This is a hereditary condition that allows the patella or knee cap to fall out of teh joint and cause pain. Your vet will have to examine Finuala to be sure this is the problem. Arthritis in this area could also cause similar symptoms.
the fact that she is able to right herself tells me that this could be a Luxated Patella and there are surgical procedures to repair this defect.
This LINK may help you understand better.
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