I’m about to start a course of hydrotherapy, you could consider that
If you do see a sports Physio and it’s muscular, ask them to do acupuncture (if they don’t do it, find one who does

). I’ve had needles stuck in all over and they’ve only helped back pain
Back pain can be referred from elsewhere or refer elsewhere, so ask the Physio to do a thorough check. Presumably if you’re new to running, you got a gait analysis before buying trainers? I’m not sure why you’ve diagnosed a joint issue? Do you have sciatica? If so definitely get checked ASAP
Try a hot bath or hot water bottle on your back at the end of every day too if you have back ache
I had surgery to resolve a slipped disc 25 years ago and my back has been pretty good considering...until I went to Prague and spent 3 days doing 000s of steps on cobbles!