Several big lumps on vaginal wall.

I've never had any big health problems and never had many sexual partners - although my current boyfriend admits to having a very promiscuous past. I have several large, painless, hard lumps on the inside walls of my vagina. I noticed the smallest one, which is very near the entrance first. I then tried to examine it further, and noticed 3 more lumps, of varying sizes and shapes, deeper in. The lumps are bigger in size the deeper they are inside. The biggest one is closest to the cervix, although I am unable to feel it properly as it is too deep. The size of each lump is about 2 inches in length and 1 inch in depth (as far as I can feel, I don't know how deep they are). I had a cervical screening test about two months ago and it came back negative. Should I be worried? I don't have any other symptoms, no unusual bleeding (although I've started to have mild menstrual pains a bit earlier than I should, if that's relevant.