did you try a hemroid cream yet .with me the cream helps take the pain away and you can relax and let the anus kind of handle healing it if it is a hemmroid.try preparation H.it helps with pain and the shrinkage problem also warm bath is soothing.good luck
could also be hemorrhoids, or a mass... not that im scaring you. better have it checked out like cheshchesh819 said since i don't know your complete history and physical examination.
Yes it probably is that,your gp can give you cream for it.