Letrozole and sore breasts

I’m on CD 9 and my doctor prescribed me 2.5mg Letrozole twice a days CD 5-9.

This is our 4 cycle with it and my first time experiencing sore breasts BEFORE ovulation. It’s completely normal for me to have them a day or two before AF but never before I’ve ovulated.

Has this happened to anyone else? I’m having a hard time finding information on it.