Hi...6 weeks out...new niggles come and go as your body adjusts to this new hip.
I had alot of lower back pain prior to my BTHR and it was mostly resolved with my surgery, but sleeping on my side took quite some time with two hips at once.
Every since then I’ve been slowly sleeping back on my side with my operated leg on top and of course a pillow between my legs but every morning I wake up with a lower back ache. Never had this prior to surgery and we bought a new mattress a year ago. I don’t have a backache during the day or even with movement all day just when I get up. Oh. And when I was sleeping on my back for the first month I never had a backache. So what’s your thoughts.
My thoughts are that tightness comes with the territory on this recovery road.
When you sleep on your side, your legs curl and alot of sitting...the same
Hip flexors are shortened in this position and tight hip flexors can cause an anterior pull on our pelvis which hurts our lower back.
My PT suggested trying to sleep on my back to be properly aligned which I struggled with this as I was not a back sleeper.
As things improve, and you can do more rigorous stretches...before bed and after getting up, it will likely get better and better.
Just my opinion. But some of these aches just seem to come around and not be totally avoided.
Trial and error was the way I got through it...and a lot more back sleeping
until it resolved fown the road.