The condition sounds complicated, it's better to have a direct contact with your physician.

It would be important to note down any changes in the pain intensity since the past few years. And give your physician all treatments you have tried.
It'll also be important to note down any particular movements that will cause pain
and show the physician how you do these movements
(e.g. bending & kneeling)

I see that you also mention about urinating,
do you ever had experience of incontinence?
there are several muscles that support the lumbar spine,
these also includes the pelvic muscles.

Some female patient after giving birth complains low back pain
due pelvic muscle weakness.

I hope some of these information is helpful.
But I suggest to give a visit with your physiotherapist/ physician