Weird cramping feeling at 34+4

Hey ladies💃🏼🤰🏽 every time I lay down then sit up, I get a really strong cramp/tight feeling in my upper stomach. Like so strong I can hardly sit up on my own. It seems to be only when I’m laying down, then go to sit up. Even if I use something to pull myself up. It was like that last night and again tonight. But I don’t have any of that pain if I lay still. Also my back has been hurting a lot more than normal last night and tonight.

Has anyone experienced this? What is it?