What's wrong with my belly on?

I got it pierced in May, it was infected for about a week in July. It cleared up and besides that it's been perfect and I'm still cleaning it regularly. Well, now...not all the time just sometimes...when I change the ring (I'll have it out for like 10 seconds) I can't get it through. There's a little fleshy/squishy thing inside and when I press down it comes out but then goes back in and its hard to take it out, its like stuck to me. Sometimes the ring will go through, other tiems it'll bleed and hurt real bad to go through, or wont at all. But if I put it in through the top (just poke a little to make sure it wasnt closed) its fine, it just wont go in from down going up. How do I fix this? What's causing it?