Well, you haven't specified whether pain is present continuously or only following passing stool. Since you haven't mentioned about bleeding, I presume that it is absent for sure.
Now taking for granted that the pain is present continuously and bleeding is absent, I guess you may be suffering from infection (acute cellulitis
). If the pain is throbbing (and if you also have fever/feverishness), you might have formed an abscess
. Another cause of severe pain
is fissure, but your symptoms are not fitting in classical presentation of a fissure. Anyway. Please consult a General Surgeon
for establishing the diagnosis and taking further treatment.