What Causes Painful And Hard Bump On Side Of Clitoris?

Yesterday I noticed a hard, pea sized bump on the side of my clitoris. It is very painful when I wipe or wash myself, sit a certain way and sometimes when walking around. I am 40 years old and have never had anything like this before. I was diagnosed with HPV 15 years ago but it was treated and have not had any problems with that since. My menstrual cycles are normal since I had an endometrial ablation last year. What could this bump be? It seems to be slightly larger than it was yesterday and still quite painful.