I get it every month too... I often have wondered if I get it before or after ovulation as well!!
I think it's before and then ends once the egg releases, but I could be wrong.
: For me it's a gradual ache, starts dull then increases alot and then decreases again to nothing. This month I thought I had O'd earlier than usual, but then we bd'd on cd13 and during/after bd I had similar types of O feeling pains -woke up the next morning and it litterally hurt to walk on my right leg and put pressure on it... by mid morning it was gone? I don't know if that is what it was, but I am secretly hoping it was later.