Hello~You sound like my husband, ever since he got out of the hospital last year, he has had excrutiating hip and leg pain, along with numbness, he never complains, but I can see the pain in his eyes. He has also had an MRI, x-ray and other tests, they all come back "Normal" I am going to have him see my chiropractor. If his and yours are due to pinched nerve, the chiropractor will be able to help; quite possibly there could be some nerve compression in these areas caused by a misplaced vertebrae and having that released by adjustments could very well help.
What kinds of testing have you had done? Have you had an MRI AND a CT scan done? Often, what an MRI misses, a CT scan might find, and vice versa. An x-ray? I'd imagine you have, but I'm always surprised at what doctors don't do.
I wouldn't tie the belt around you at all, as you don't know how much is too much, and no one can determine that, but that would be good information for your doctor to have. It might help identify the problem.
https://www.mayoclinic.org/symptoms/hip-pain/basics/causes/sym-20050684 - there's a list of possible causes of hip pain. I wonder if you limit the blood flow to the area if you are helping with inflammation.