Heavy full breasts from breastfeeding causing back pain?

Kat

Im experiencing extreme middle back spasams since my son is now sleeping through the night, my breasts are way more full with him sleeping through his regular feedings since he's not getting up every few hours, then by morning the pain is excruciating in my back until he is up and eats, then the pain is completely gone for the rest of the day until night comes again he sleeps and here is tge cycle all over. It makes the extra sleep way less enjoyable, I've never experienced this before which is why I'm reaching out for advice. I'm concluding this to be caused by full breasts. I have started doing some core strengthening excersise but hard to find the time with an 11 week old And older son a husband And a house to take care of. Just seeing if anyone else has experienced this. As I did not with my first son and my breast size went up to this same size with him also.

Hope everyone is doing well with their July 2018 babies :) the time is going by to quickly.