hello sir it is good to know you have recovered quite a bit from the pivd pain as far as 1 yes you should take care of your back as it is the most important thing in your body which supports your weight and makes us walk on two legs 2 yes your numbness may get cured but the time required is uncertain generally as some residual numbness may occasionally come up , you need to take neurotrophic drugs such as vit b 12 or methylcobalamin 1500 micrograms daily 3 yes you can resume physical activity but try to refrain from contact sports , and whenever you plan to resume actives ,first try to build up your back muscles and abdominal muscles as they would help you . try not to engage in activities which may cause loading of spine 4 yes you should take precautions do warm up before physical activities , take neurotrophic drugs and strengthen back and abdominal muscles in case you need further clarification write to me