Is ur swelling hard? Painful?...any pimple or boil on that side of hip or area? It can anything like abcess or hidden sinus beneath..underdeveloped ca or piles or fibrosis and so on....
Basically it's not possible to diagnose anything without physical examination or atleast pic of that part.
It's better u consult any ayurvedic surgeon only because ano rectal cases are best treated in ayurveda and not allopathy
Next Steps
consult here for further guidance
Health Tips
hot fomenting that part..
isabgol at 4pm and after taking it drink 1-1 glass warm water after a gap of 1hr