Welcome to health care magic. 1.Suggest you to see a doctor for this issue - the reasons is there are quite a few complications for the lumps on the tail bone / perianal region. 2.Mostly possible cause will be hair follicular infection / infective aetiology which is causing pain and tenderness. 3.The treatment in this case after examination a course of antibiotic ( if small one) 4.If not responding to the treatment or larger in size then a small incision and drainage will be necessary. 5.The complications are pilonidal sinus, fistulas ( which needs operative treatments) so treat it as soon as you can - take good post procedural care. Good luck. Hope i have answered your query. Any thing to ask do not hesitate. Thank you.