I had really bad stomach aches/bloat after morning swims when I was working. I'm retired now and amazingly it has disappeared. I'm sure it was due to gas in the gut but I never understood how it got there because I swear I didn't/don't swallow that much air when swimming. When I had it bad it would last about four hours and hurt like hell until it passed :) Back then I would get straight out of bed and hit the pool. No coffee, no food. My new retirement routine is to get up and drink coffee, hit the bathroom, and have a banana and maybe a GU before the swim. Still have occasional gas but it passed so much faster, easier, and without the bloat. Good luck with it. I almost quit swimming because it was so bad. Interesting enough; never had stomach pain after a triathlon race swim (and I've done over 100).