You don't have kidney stones do you?
So sorry you are going through this. Just 2 cents as I was thinking I got awful pain in my lower back when a stone was "on the move".
Wouldn't that involve cancium? I have so often like almost no relief that I would have to have alot of stones I mean I can barley walk afraid of moving the wrong way. Also I had a little protein in my Urine does that mean anything like is my kidney still functioning o.k.? I tell you if I knew what I know today I wouldn't just have had my thyroid taken no way that being said I just have to keep plucking away at solution nothing is going to get better from here.
Protein in urine......then definetely u have some problem with kidneys. My father-in-law is a dieabetic and his tests showed protein in urine...when he went for medical check they told his right kidney totally gone. He removed that kidney. So please check your kidneys...Kidneys are not filtering the "albunin"then it really gor sick.
I've had lower back pain as well since I started on synthroid. . .actually a bit before when I was on the PTU as well. . .I wasn't sure if it was from going Hypo or from the weight that I have put on as result of my treatment. . .I'm leaning toward the weight gain. . .
best of luck to you!