OMG, bras.
I've gained a bunch of weight in the last year, and my bras were no longer fitting (as in, they were somewhat painful to squeeze into.)
So, here are a couple suggestions...
Nordstrom's actually has some bigger sizes in their stores and online. The person I worked with in the store was wonderful, not at all pushy and really helpful in figuring out what I needed. But, obviously, their stuff is a bit pricy. I ended up with the "Wacoal Awareness Bra" (with an underwire, in an embarrassingly large size) - but it fits and is comfortable.
They also have free shipping from their website (and I think free shipping for returns), or return to the store. And, you can see from the website what's in stock at the store - so I picked out a few online that looked promising and were in stock locally to go try out. That worked great.
But, they don't seem to have a great selection of larger sports bras. Ugh.
So, today, I found out that Kohls, of all places, does have quite a few larger size sports bras (online only). If you order more than... $75 (I think) shipping is free... and you can return to the store for free (I have a store close by). So, I ordered 4 different sports bras (!) and will just plan on returning them all if none of them fit. I'm really hoping at least one will work for me.
(Special note: if you order the "Glamorizer" bra, which Kohls carries, they do their sizing different from anyone else. Check out their website to estimate. If you order your normal size, it likely won't fit - because they base the band measurement on the top of your breast, just under your underarm (!!!) which is likely a couple inches bigger than your ribcage.)
Phew. Sorry, I've been obsessing about bras lately, and am sort of happy to get to share my hours of web searching
I tried to squeeze into an old workout bra that was literally falling apart today. Since it was (literally!) ripping - I thought I'd be clever and fasten it on the tightest level, which would bypass the ripping part. Uh, no. I got STUCK IN IT. I couldn't get it to turn around, I couldn't squeeze any more to undo the latches, and it somehow migrated down to a fatter part of my body, apparently, and became 1000% stuck. I had to cut the bra to get out of it! Really scary moment there!