Does a pinched nerve in upper back cause pain and weakness in both legs?

Spinal cord symptoms. A "pinched nerve" in the upper back can indicate possible compression of the spinal cord. This can lead to pain, numbness, difficulty with balance, bowel/bladder issues, and weakness in the lower extremities. This type of disease may be quite serious and should be evaluated by a physician.
It my depending on . The cause of the pinching, its location and degree. Generally, this would be known as a myleopathy with actual compression of the spinal cord which typically ends at rhe L1 level in adults. If this is the case, this is usually progressive and needs to be addressed surgically.