Pain/pinching on side after letrozole?

So Im on CD9 after taking letrozole for the first time from CD3 to 7 for my first IUI cycle.

Today I’m feeling twinges and pinching on my right lower area. Similar to ovulation pain.

Did a opk this morning and was very negative so can’t be ovulating this early.

I have my follicle check tomorrow! Hoping for the start of big juicy follicles!

Did yall feel this kinda pinching? Is it my follicles growing?