Our dog.. a nine year old cocker-bischon... is having trouble getting up stairs... and jumping on our bed... something with her hind legs... otherwise she seems fine

Arthritis probably. Try glucosamine. A water bed, or heated bed. I have had to make a step for my little dog at both my couch and bed. I just use a box or bin about half the height but you can buy carpeted steps. I think my dog will need 2 steps soon instead of 1.
I also keep a heating pad on low on the couch for her in the wintertime and she zeros right in on it.