Hello I really appreciate your concern You need not to worry, Looking at your description it seems to be a treatable condition and you will be alright once you start treatment after consulting doctor. In my opinion this could be hemorrhoids, anal skin fold or infected anal gland. Another possibility is fissure in anus or an abscess I would like further information like your age and relevant medical history since how long you have this problem I would advise you to avoid constipation by taking laxatives or stool softening agents like liquid paraffin or lactulose Sitz bath twice daily lignocaine ointment to be applied locally to relieve pain Hope this helps you best wishes