What Causes Grey Vaginal Discharge?

I have had fairly heavy grayish discharge from my vagina off and on for about three weeks. A month and a half ago I started a new birth control pill. I am unsure as to whether it is that, or if it may be because I put lotion all over my body and recently got a new scented lotion and maybe from putting it near my vagina it may have gotten onto my underwear and somehow into my vagina. There is no irregular itching, no odd odor, and no discomfort. But I have never had gray discharge before and it is concerning me.