Any ideas what this could be?

For the past two and a half years I have been dealing with chronic low back pain and pain in my hips along with stiffness. The low back pain is right where my back ends and my backside begins. It is worse in the morning and after doing a lot of standing or walking. I have no numbness or tingling. My hips are always out of alignment which causes my leg left to be longer than my right. Also my left hip over rotates and my right hip doesn't rotate enough. I am just looking for suggestions of what it sounds like it might be so I can bring those things up to my doctor and we can rule them out with testing.

I am female, and I've had two very large babies. I am currently on my third round of pt. It seems to help a little during, but between the sessions, I seem to return back to where I started. I am going to keep on with the pt, do another round of si joint injections and attempt to get a referral to a rheumatologist.