I have a bump on my tailbone. looks like a cyst. should i see a doctor?

A pilonidal cyst: Pilonidal=nest of hair. Aka sacrococcygeal fistula, is a cyst or abscess near or on the natal cleft of the buttocks that often contains hair and skin debris. When infected, it can cause quite a bit of pain in the rear-end. If it is not bothering you, you may not need to do anything. If infected and painful, you may need it drained and/or antibiotic etc.. Consider consulting doc. Good luck.