Endometriosis - Most common cause of Infertility? Symptoms, causes, treatment

What is endometriosis and how common is it?
What are the key symptoms of endometriosis and why do they occur?
How does endometriosis lead to infertility?
What is the cause of endometriosis?
How is endometriosis diagnosed?
Which organs are most commonly affected by endometriosis?
What are the common and serious complications of endometriosis?
What are the first, second, and third line treatments for endometriosis?
Highlights:

Endometriosis is a chronic condition where tissue similar to the endometrium grows outside the uterus, affecting around 10% of women.
The main symptom of endometriosis is severe pelvic pain, particularly during menstruation, sexual intercourse, and bowel movements, caused by trapped bleeding from the endometriosis implants.
Endometriosis is strongly linked to infertility, potentially due to adhesions caused by the implants interfering with egg and sperm movement.
The cause of endometriosis isn't fully understood, but it likely has a genetic component and is associated with retrograde menstruation.
Endometriosis is definitively diagnosed using laparoscopy, a surgical procedure that allows visualization of the pelvic organs.
Endometriosis most commonly affects pelvic organs like ovaries and fallopian tubes, but in rare cases can affect bowels, skin, lungs, and even the brain and spinal cord.
Common complications of endometriosis include infertility and ovarian cysts, with a slight increase in the risk of ovarian cancer.
Treatment for endometriosis primarily aims at managing pain and includes medications, hormonal therapies, and, in severe cases, surgery