Well until you get your results, I suppose you can worry if you find you can't resist. If your doctor said you have too tight a cervix, maybe he is right. Did he have you do any blood tests? I'm 19 and have had irregular periods for 6 years, and my doctor had me do bloodwork to make sure my hormones and thyroid were normal. They are, and it turns out my ovaries just don't like to ovulate when they should. I'd think your doctor would have checked those kinds of things first before doing a pelvic exam. And if he did do blood work, then I would go with whatever tests he wants to do to get to the root cause of your problem. If everything else about you is normal, it's probably not hormonal. Just saying. Not to say that other person isn't right, but just saying, things like this can't just be dismissed as simply hormonal because when they are an "always" thing where they've always been this way, they're usually not hormonal.
I have a wondeful site that maybe able to help you with your menstral problems but I'm not allowed to post it on here if you would like the indo just message me, it sounds to me like your period problems are more hormonal than due to your cervix