Exercising with big boobs

If you have insurance with that size of breast, you could probably qualify for breast reduction and insurance would pay the majority of the cost! I had it done about 7 years ago and it was the BEST thing I ever did for myself. I have never regretted it for a second.
I had no idea how many things it kept me from doing until I had them cut off!

I bought my sports bras on ebay! 60 to 80 dollar bras for 15-20 dollars. Go try on some high-end sports bras to see what size feels good, then watch ebay. As others have mentioned I like Anita, Freya, Panache and my current favorite is Wacoal, it has underwires on the outside and holds well. These bras come in larger uncommon sizes-multi letter ones. Bras on ebay are often store demos, hard to sell sizes, gently used, and unreturnable bras that were worn a few times and determined to be the wrong size for the seller. Or closeouts.
I had to get a good supportive bra, did Jillian Michael's 30 day shred and the plank jacks made my boobs bounce so hard I injured a ligament and couldn't even take a shower without intense pain. (Heavy weight of unsupported boobs hurt!!) Had to hold myself when dressing, showering, etc. Took a while to heal. I learned to modify my movements to keep the bouncing to a minimum.