Dog pees everywhere?

My 9 year old yorkie started peeing everywhere. She is house trained. She also has some back and knee problems but she gets daily medication for it and I carry her over any steps. She's pretty energetic and jumps and runs regardless. She started peeing in the living room regularly (it's where their food is and where they spend most of the day) instead of going up the hallway step and peeing in the bathroom on the pee pad. I've watched her sometimes hesitate in front of the 15 cm step even though she just jumps over it constantly.

I've since then blocked off majority of the living room because she repeatedly goes, and also installed a ramp up the step in case it's hurting her back (she doesn't like to use it and usually just jumps over, but I'm forcing her to.) I reward her for going up the ramp and praise her for going on the pee pad. She STILL keeps peeing everywhere, even in other rooms past the bathroom??? Sometimes she pees a lot, like she's been holding her bladder.

She had never done this before in her life and I'm losing my mind. I've been thinking about diapers? I clean pee off of the living room floor every 2 hours or so…….. I really don't want to put a pee pad there because I fear it will reinforce her idea of peeing there, and also the other dog will pee there too.

Edit: she also poops at those places as well. This has been going on for 2 months now 🙁