Pregnancy boob pain!

I am 13 weeks pregnant with my 2nd baby.

My eldest is 8months and I pumped for her for the first 5 months as my extremely strong let down made breastfeeding directly impossible.

I had no issues with tenderness during the first trimester, but today I have started having a lot of breast pain, it feels like I’m letting down constantly and the pressure is just building and building with no release.

I just want to know if this is normal with a second pregnancy? Has anyone else has experienced this? Or has any advice?

I have tried the usual, heat pad and massage but am scared to do much more incase I jeopardize my developing milk supply!