IRCT2016011824621N4 IRCT 2016-02-17 Vice chancellor for research, Iran University of Medical Sciences the effect of biofeedback therapy in the treatment of coccygodynia a clinical trial on the effect of biofeedback therapy in treatment of coccygodynia in patients referring to physical medicine and rehabilitation clinic of Firoozgar hospital 2016-02-20 anticipated 30 Complete https://irct.ir/trial/20747 interventional Randomization: Randomized, Blinding: Single blinded, Placebo: Not used, Assignment: Parallel, Purpose: Treatment. 2-3 coccygodynia. Intervention 1: in the intervention group local injection of 1cc Lidocaine and 1cc of 40 mg Methylprednisolone in the point of maximum tenderness plus teaching of pelvic floor exercises for 4 weeks and lifestyle modification plus pelvic floor biofeedback. biofeedback is a kind of physiotherapy which is done 2 sessions per week, each time for 15 minutes and in total number of 8 sessions for 1 month by a physiotherapist. Pelvic floor exercises are done 3 times a day, each time for 5 minutes by the patient. Intervention 2: in the control group local injection of 1cc Lidocaine and 1cc of 40 mg Methylprednisolone in the point of maximum tenderness plus teaching of pelvic floor exercises for 4 weeks and lifestyle modification. Pelvic floor exercises are done 3 times a day, each time for 5 minutes by the patient.