TAH swelled belly Only at night following hysterectomy

I wake up, I'm soar I get moving in okay, by 4pm I'm having swelling, and pain, what could this be and what can I do.?

It sounds like classic swelly belly. What you can do is wait it out. It should get lesser and lesser over time. Give it a while. It should get a bit better. The only trick I know is that if you want to have a smaller belly in the evening, lie down for a couple hours in the late afternoon. That helps sometimes.