<s>[INST] I have a red, painful, hard lump at the very top of my butt crack. No puss. Really concerned as it has been getting more painful over the last couple days. I have been doing some DIY recently and was sitting on hard decking for a day while painting. The symptoms started shortly after. It is about an inch in length and sore to the touch. Please help, advise what it might be and whether I need to see and doctor? Thanks [/INST] Hi, dear. I have gone through your question. I can understand your concern.  You may have some pilonidal sinus. It is common due to sit on hard place. You should consult your doctor and go for examination. Then you should take treatment accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using health care magic. Wish you a very good health. </s>