Urological causes  

Urinary bladder carcinoma

Recurrent urinary tract infections

Interstitial cystitis

Radiation cystitis

Urolithiasis

Urinary bladder overactivity

Urethral diverticulum

Female urethral syndrome

Pelvic floor spasm

Gynaecological causes

Adenomyosis

Pelvic adhesions

Genital cysts

Dysmenorrhoea

Cervical stenosis

Endometrial and/or Cervical polyps

Endometriosis

Leiomyomata of the uterus

Residual ovary syndrome 

Pelvic veins congestion syndrome

Vulvodynia

Gastroenterological causes

Large bowel carcinoma

Intermittent intestinal obstruction

Colitides (In general)

Constipation

Diverticulitis

Inflammatory bowel disease

Irritable bowel syndrome

Post surgical adhesions

Musculoskeletal-Neurological causes

Pain of abdominal wall

Spinal disk prolapse

Not correct sitting or standing body attitude

Fibromyalgia

Hernias

Central nervous system neoplasms

Mononeuropathy

Polyneyropathy

Pelvic floor spasm

ANALYSIS BY GENDER:

Endometriosis

This is a condition in which tissue from the uterine lining (endometrium) grows outside the uterus. These deposits of tissue respond to the menstrual cycle, just as  uterine lining normally does — thickening, breaking down and bleeding each month as hormone levels rise and fall. Because it's happening outside the uterus, the blood and tissue can't exit the body through the vagina and become trapped in the abdomen. This can lead to painful cysts and adhesions (fibrous bands of scar tissue). 

Tension in pelvic floor muscles

Spasms or tension of the pelvic floor muscles can lead to recurring pelvic pain. 

Chronic pelvic inflammatory disease

This can occur if a long-term infection, often sexually transmitted, causes scarring involving the pelvic organs. 

Pelvic congestion syndrome

This is a condition that may be caused by enlarged, varicose-type veins around the uterus and ovaries. 

Ovarian remnant syndrome

During a complete hysterectomy — surgical removal of the uterus and ovaries — a small piece of ovary may be left inside, which can later develop tiny, painful cysts.

Fibroids

These noncancerous uterine growths may cause pressure or a feeling of heaviness in the lower abdomen. They rarely cause sharp (acute) pain unless they become deprived of nutrients and begin to die (degenerate). 

Irritable bowel syndrome

Symptoms associated with irritable bowel syndrome — bloating, constipation or diarrhea — can be a source of uncomfortable pelvic pain and pressure. 

Interstitial cystitis

Chronic inflammation of the bladder and a frequent need to urinate characterize interstitial cystitis. The patient experiences pelvic pain as the bladder fills, which may improve temporarily after emptying the bladder. 

Psychological factors

Depression, experience of chronic stress,  or a history of sexual or physical abusion, are more likely to contribute to chronic pelvic pain. Emotional distress makes pain worse, and likewise living with chronic pain makes emotional distress worse. So chronic pain and emotional distress frequently get locked into a vicious cycle.  

Possible tests or exams that we could suggest are:

Pelvic examination

Cultures

Laparoscopy

Imaging studies