It could be pregnancy or it could be af starting to make her appearance.
I usually get sore boobs before af and every month I would think do my boobs feel sorer this month.
Every one is different for symptoms and signs of pregnancy.
My boobs did feel fuller and a little sore but nothing major, I was urinating more...but for me the main thing was feeling completely wiped out and constant lower back pain which just wouldn't let up, even now i have my bfp it's still here.
But as I say everyone is different.
You can take a test 2 weeks after last sexual contact, which by then should give you an answer!