Where is it located exactly? I had a bump on the top of my tailbone...about an inch below where my crack starts and it was a Pilionidal cyst. Let me tell you, it hurt like hell to sit, ride in a car, walk, etc. I had surgery to remove it and now I'm left with a giant hole that "will heal on its own". My recommendation to you is to take hot baths-as hot as you can possibly stand it, use a heating pad 20 minutes out of every hour, and take tylenol for swelling. If it gets worse, go see a doctor-more specifically a surgeon if you think it's a cyst on the tailbone. Sometimes things like this will pop on it's own and the heat will aid that. I can't stress to you enough how heat is going to be your best friend!