Pain just inside anus. The findings may seem counterintuitive, given that marijuana increases appetite. There are many causes of anal pain but most are easily treatable. Products and services. Sign up now. For this treatment, an anesthesiologist puts a small needle into the person's back and injects a solution that numbs the nerves in the pelvic area. Seek immediate medical care if you experience: For some people with proctalgia fugax, they may experience severe muscle cramps in their anal canal. When this happens, the rectum may protrude out from the anus. Women may be impacted by any of the previous conditions. This is typically a result of injury in or around the pelvis, torso, or back. A thrombosed hemorrhoid is an especially painful, but not necessarily serioustype of hemorrhoid as it involves a blood clot in the vein.