Pain in pelvic, could it lead to something more serious?!

Pain in pelvic, could it lead to something more serious?

"Pelvic pain during menstruation or ovulation can be a symptom of endometriosis, but may also occur in normal women. "
I found that on a website, and I could be the "normal" one but I wanted to make sure. My last cycle was about a week and a half ago.

This isn't the first time I've had it, although it doesnt occur that frenquently. It feels like a needle poking me. I'm only 17, it cant be ovarian cancer, right?

Is this a symtom of something much worser? What could this be a possible symtom of?

Also, could this just be happening because I hold in urine for more than 5 minutes? (maybe its a bladder problem?)

I too have endo and it is far from fun. At the same time what might be a needle to one could be a bomb to another. It all depends on your tolernece for pain. I was miss diagnosed for 5 years, because I did not describe my pain accurately for my doctors. I always believed that there was much worse pain out there, because everyone always told me I was over reacting. When I was diagnosed I was in stage IV and the endo was growing into my colon. I had the choice between laparotomy followed by Lupron or hysterectomy.
So my advice would be to tell your doctor about what you are experiencing and be as honest about the pain as you can. Do not let someone convince you about how the pain feels to you. And if you do not trust the answers you get from your doctor ask for a second opinion.