Anal Fissure: This is a common cause of rectal pain, especially if the pain is sharp and worsens with defecation. The pain is usually due to a tear in the lining of the anus.

Hemorrhoids: Both internal and external hemorrhoids can cause rectal pain, though external hemorrhoids are more likely to cause pain due to their location and potential for thrombosis.
Proctalgia Fugax: A condition characterized by fleeting rectal pain, often at night, with no clear cause. It can be very painful but is usually brief.
Levator Ani Syndrome: Chronic pain in the rectal area due to spasms of the levator ani muscle. The pain is often aching and can last for hours.

Rectal Cancer: Although less common, rectal cancer can present with rectal pain, especially if the tumor is large or has invaded surrounding structures.
Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause rectal pain, along with other symptoms such as diarrhea, blood in stool, and weight loss.
Ischiorectal Abscess: An abscess in the ischiorectal fossa can cause severe rectal pain, fever, and swelling. It requires prompt drainage to prevent complications.
Thrombosed External Hemorrhoid: While not always life-threatening, a thrombosed external hemorrhoid can cause severe pain and may require surgical intervention for relief.

Coccydynia: Pain in the coccyx (tailbone) area, which can sometimes be referred to the rectum. It's often due to a fall or trauma to the area.
Pudendal Neuralgia: A condition involving the pudendal nerve, which can cause chronic pain in the rectal area, as well as other areas innervated by this nerve.
Solitary Rectal Ulcer Syndrome: A condition characterized by ulcers in the rectum, often associated with chronic constipation and straining during bowel movements. It can cause rectal pain and bleeding.