Urinary Tract Infection (UTI): This is a common condition that can cause hematuria, especially after sexual activity, which can introduce bacteria into the urinary tract. Symptoms like pelvic discomfort and lower back pain are also consistent with a UTI.

Kidney Stones: These can cause severe pain, often radiating to the lower back, and can lead to hematuria. The pain can be intermittent, which fits with the "on and off" description.
Cystitis: Similar to a UTI, but specifically referring to inflammation of the bladder, which can be caused by infection, irritation, or other factors. Symptoms include pelvic discomfort, hematuria, and pain.
Endometriosis: A condition where tissue similar to the lining inside the uterus grows outside of it, leading to pain, spotting, and potentially hematuria if the endometrial tissue involves the urinary tract.

Bladder or Kidney Cancer: Although less common, these conditions can present with hematuria and pelvic or back pain. Early detection is crucial for treatment outcomes, making them critical not to miss.
Ectopic Pregnancy: A pregnancy that develops outside the uterus can cause severe pelvic pain, spotting, and potentially hematuria if there's associated bleeding. This is a medical emergency.
Appendicitis: While the primary symptom is abdominal pain, in some cases, especially if the appendix is located near the urinary tract, it can cause urinary symptoms including hematuria.

Interstitial Cystitis: A chronic condition causing bladder pressure, bladder pain, and sometimes pelvic pain. The symptoms can overlap with those of a UTI but are more chronic and less likely to be associated with infection.
Schistosomiasis (Bilharzia): A parasitic infection that can cause hematuria, particularly in individuals who have traveled to or lived in areas where the disease is common. It's a rare cause in most Western countries but should be considered in the right epidemiological context.
Arteriovenous Malformation (AVM) or Arteriovenous Fistula (AVF) in the Kidney or Bladder: These are abnormal connections between arteries and veins that can cause hematuria and potentially other symptoms like pain, though they are rare.