Sore lower back when I stand more than 20 minutes and lie on your back

Question from Anton Sobyanin:

Sore lower back when I stand about 20 minutes. The longer, the harder. Begins to burn. Exactly the kind of pain occurs when lying on my back. With the legs bent when the pain subsides. The pain began in February. I am 46 years old.

Answer:

The Clinical picture is similar with either compression of a nerve in the lumbar-sacral spine, or with compression of the "horse tail" lower part of the spinal cord. The lack of pain when bending knee indicates the presence of the symptom of muscle tension, which disappears after removal of the load from the muscles of the lower limbs.

I can Advise only performing radiography, computed tomography or MRI of the lumbar. After that a qualified doctor can set the diagnosis. Without diagnose can't give recommendations.