This is tenderness of coccyx which may happen due to local herpetic infection or pilonidal cyst or fracture of tail bone or pain in sciatic nerve (referred pain) or sacroillitis. If you have herpetic infection than there must be definite painful rash associated with itchy blisters. Check for X-Ray of pelvis to exclude rest of possibilities. If all tests are normal,than you may be suffering from referred pain of sciatic nerve along tail bone,which may be detected by NERVE CONDUCTION VELOCITY TEST OF SCIATIC NERVE IN both side.
Usually, conservative management cures tail bone tenderness. I shall prescribe you medicines if you consult in private. When pain subsides,than you need to attend physiotherapy daily for 1month. If tailbone pain is continuous and unbearable, than coccyx bone may be resected by any consultant orthopaedician.
You should also avoid strenuous exercises and avoid bike riding,which increases such pain. You may apply hot water bag under your tailbone and sit for 20mins for 3-4 times daily. Take complete bed rest for 5days while taking conservative management.