The severity of the symptoms depends on the degree of nerve compression. If the nerve is compressed by a herniated disc in the lumbar spine or cervical spine, the patient may experience numbness and weakness in the limbs, and some patients may experience radicular pain, such as sciatic nerve pain after compression of the sciatic nerve. If the spinal cord is compressed, the patient may also experience urinary and fecal dysfunction. Some patients with compression of the nerve, such as cervical disc herniation, will have pain in the back or shoulder and difficulty in lifting the hand. So what happens when a nerve is compressed depends on the degree of nerve compression.