After reading what it is, it appears to me to be what I called a big ole boil.
My poor grand-daughter had one just like what is described. I took her to the doctor and they lanced it and she has been all right ever since. Not to say it might not come back.
Although it is very uncomfortable having one of these it does not cause such pain that someone would take heavy duty pain medication for IMO.
From the article on pilonidal cyst.
"Most people are free of further problems with pilonidal cysts after drainage alone or after surgical removal of the cyst. However, in some cases, even after surgery, the cyst can come back. The reasons for this are not known; a new cyst can form from an ingrown hair, or it is possible to have another congenital cyst flare up at a later time. When this happens, surgery can again be done, again as an outpatient, with the exact nature of the procedure dictated by the nature of the recurrence."