Mucus like vaginal discharge, what is it?

I'm 15 years old. I'm still a virgin.
I've had slight issues with this for the past 3 or so years.
But I was little still, so I ignored it.
But, I have vaginal discharge that varies from yellow - to clear - to whiteish.
The smell varies as well, sometimes you can't smell it. Sometimes you can.
More recently, it's causing pains and cramps. The amount has also increased.
I can feel it, through-out the day.


Is this normal?! what is it?!