Hi and welcome to the MS community, not sure why your question landed in the MS community and not neurology or Thyroid communities.
Honestly, from what i've been looking up its an unlikely causation of your lower back pain already but considering all your mentioned medical issues.....
"pituitary dwarfism", "osteoarthritis of the spine and nerve damage in arms", foot drop? ("I also trip and fall a lot somehow I don’t get my foot high enough. Ankles hurt a lot but foot doctor doesn’t know what is wrong yet. Have seen him 2 times this year for severe ankle strain. And put in a boot to wear. "), "parathyroid / hypothyroid / hyper parathyroid", "Osteoporosis in neck and lower back osteopenia in hips" etc
...one or more of these medical issues could potentially be the cause of it and because of your complicated medical history there may not be able to pin it down to any specific cause.
Hope that helps a little, sorry couldn't help more........JJ