Hello there...  Once gone through this,  hope u might be knowing that the pilonidal cyst or sinus as we call it,  is a result of sweat and hair collection at your sacral area.  The pain starts and increases when secondary infection sets in.  Treatment consists of total Excision and cover.  Getting the Excision done through a surgeon, who'll excise the deep sinuses in total will decrease the chances of recurrence..  Few medications post surgery,  to reduce the amount of sweating might also help.