I had something similar happen to me almost 2 years ago. It went away after a week or two and i have no idea what it was but i would recommend stopping just for now.
Worried about My Inflating Belly
So I've been doing inflation for about a year now, filling myself with air and distending my belly, but something happened that worries me.
Normally, when I inflate, my belly begins to ache when I go too long. But last week, I was inflating for about 20 minutes. At that point, my stomach begins having its usual pains, but this time, it didn't. Not like I'd adjusted to it, but I inflated for about 35-40 minutes before I knew it was time to stop. I had myself checked out, but nothing ruptured.
Is this normal for veteran inflatees?
Eh, I honestly have no idea because I haven't actively tried to increase my capacity past a certain amount. I've heard a while ago that it could be restricted blood flow and the nerves are being numbed, but I'm not actually sure if that's true or not, and I don't know the physics or biology to prove it.
Like the others have said, just take a break and don't try to push yourself too far. There really isn't a guide for things like these so we just have to play it safe for now.
You've damaged your abdominal stretch receptors. I suggest stopping