Sore back

Millie is 9, 10 on Sept 1st. Almost three weeks ago I noticed she was a bit stiff, and when she screamed getting up the next morning we went straight to the vet. She was slow putting her rear paws back when the vet turned them. She was prescribed Metacalm and to go back in 2 days.
There was no improvement, if anything slightly slower correcting rear paws so tramodyl was added and referral to Glasgow for MRI. Appointment became more urgent when I realised she was holding her pee for 16 hours, then 28 hours.
In Glasgow SAH she didn't get the MRI scan because she was stressed and has a heart murmur I was told was grade 2 in Feb, but was prescribed gabapentin and 4 weeks rest for possible degenerating disc and/or SM.
Got report today, almost 2 weeks later - heart murmur grade 2-3/4 !!!
Advice please on any of the above - disc, SM, DMVD

Here is a webpage on intervertebral disc disease in the CKCS. http://www.cavalierhealth.org/disc.htm If she was my dog, I would start with acupuncture and chiropractic at a really good holistic vet office.