What To Do For Sore Tail Bone Which Causes Pain When Sitting And Cycling?

I am a 58 YO female, recovering from breast cancer and treatments which started a little over a year ago. My tailbone has been terribly sore for over 4 months. There was no trauma to the area and no outward signs of a cycst. Because my hair started coming in close to the time the pain started I wondered if they could be related. Had x-rays yesterday but don t know results. Could you make any recommendations. Sitting and cycling can be very painful. Thanks.