Ovulation pain but negative opks

Reka • Expecting baby #2 🐣😍
I'm having slight pain near my left ovaries but my opks still show negative. This is my first month using them. Im on CD15 and my cycles range from 27 - 29 days (but usually 28). I never used to pay attention to this stuff so i don't know how it works. Do you get O pain before, during or after ovulation?? Why am I still testing negative for LH??