why do my nipples hurt?

Gemm💖 • Met my 💝 01/01/2011, 💍 1/02/2012, Bought our first 🏠 01/06/2015. 👼 baby 17/08/2019. Wifey 🤵🏼‍♂️👰🏻‍♀️14/07/2021 👼19/07/2021 Ttc first baby for 7 years!
Iv been ttc with my fiancé since December with no luck, we thought that we were this month as my period was a week late.. when I actually got it on he 4th January it was light or even spotting for 2 days then medium for a day then back to light spotting.. not even filling a pad (sorry tmi). A week after my period my nipples have been hurting badly... any ideas what's happening?is it to do with ovulation? I'm new to all this..