Suggest Treatment For Cyst On The Buttocks Near The Rectal Area

I have a cyst like in my right butt cheek right near my rectum. This seems to fluctuate in size from the size of a pinkie finger to thumb size. Up to today the size has increased and is sore to sit on. I am a female 41 and have not had cancer before but my mom has had colon cancer. I have already had a colonoscopy 7 years ago and it was clear. I lost my job and for first time in my life I am without health insurance so I have put this off for about 6 months. Is this possibly a cyst?