One can rupture an internal hemorrhoid with no previous symptoms and no pain at time of bleed. Basically, hemorrhoids are just varicose veins and anything that increases abdominal pressure (heavy lifting, straining, childbirth, etc) can cause them.
Since the tissue there is so fragile, it takes very little for one to rupture.
They bleed like crazy and aspirin/ibuprofen would increase bleeding time.
Fissures and tears usually hurt like the dickens, especially fissures. In any case, you HAVE to see a doctor ASAP.
hemorrhoids can be repaired on an outpatient basis and from what I understand, it is now done as cryosurgery and isn't nearly as painful as it was in the old days.