What Causes Back And Neck Muscle Tightness With Tingling And Weakness?

My husband had a discectomy which is healing well. However, now he has a lot of muscle tightness in his back and neck. When he lays down, his hands and feet go to sleep. He is having strange tingling in both arms and legs at times along with a feeling of general weakness. He was tested for vitamin deficiency, but we don't have the results yet. How worried should we be? How long will it take to get relief, assuming we find the cause?