Oh, I had this so badly along with my horrible nausea in the first trimester. Honestly, even a warm shower or applying a cool pack for 5 minutes can give you so much relief. It's just your body adapting, hang in there!
It's completely normal, yaar. It's just the pregnancy hormones like estrogen and progesterone prepping your body for breastfeeding later. Get a good, seamless maternity bra without underwire, it makes a huge difference.
It's because your body is already starting the beautiful process of preparing milk for your little one. I remember feeling so tender and emotional about this change. It will get much better after the first trimester, trust me.
I am currently trying to conceive and keep reading about this symptom! Is it like a constant heavy ache or does it come and go? Hope you feel better soon!
Don't go buying expensive things for this. Just switch to a comfortable cotton sports bra or non-wired bra that is one size bigger. Avoid tight clothes for a few weeks, and it will settle down on its own.