I don't know. But I have the exact same thing.it just out of no where started throbbing in my right ovary. Its so annoying. I thought it was cause I had chlamydia. Or I havent go my shot for hpv. So you might want to get checked out.
It could be your ovaries or your appendix or it could possibly be a kidney infection have you tried taking a nice warm bath it could help.
Its on both sides in your lower stomach area. Can you feel it towards your lower back also? Do you drink alcohol? Did you tie one on recently(last night, or the night before). If it is what I think it is, its not serious, but it should only last a couple days. If you ever drink, this is one of the effects. Pain in your kidneys. Try drinking 8 glasses of water in the next 2 days.