Back stiffness and tail bone pain

Hi, I have been suffering from back pain(more of stiffness) since last 6 months. Also,i get severe pain in my tailbone which spreads to my legs and feet as well,due to which I can’t exercise.Xray and MRI reports show everything normal except swelling in last 2 discs and some swelling in tailbone. The doctors say it is due to prolonged sitting.Please help,as the Doctors say that everything is normal, but I really feel so much stiffness in my whole bacl whenever I sit or drive car. Also,at a time I either feel stiffness in my back or pain in tailbone.