Hello,
Three possibilities are there for such a painful anal grwith.It can be fissure in ano,haemorrhoids or anal fistula. Diagnosed by clinical examination,Per rectal examination and anoscopy.
I would suggest that you get an examination done from a general surgeon to confirm the diagnosis.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional queries.Kind regards.
A pile mass,fissure in ano would be the two conditions.Consult your doc.Anovate ointment would help