Hello everyone, don't think it's a stupid question, just that I'm not …

Hello everyone, don't think it's a stupid question, just that I'm not quite sure ? It feels like my belly is inflating on the right side, like a balloon. The pressure is... and on the left it's softer, but this happens irregularly. It inflates and then goes back to being soft. What could this be? I understand that I'm already in my due date, my uterus should start growing, most likely just the uterus itself. But why only on the right side do I feel it?