Please tell me how to properly say these sentences?

Could you please tell me how to say these sentences correctly?

- The feeling I have is as if you constantly had a cramp in the stomach. That's how bad/much it hurts.
- What/which saturday of the month do you work?
- My back won't be hurting/won't hurt by the time I wake up. Hopefully you'll get/be better by then.
- I'm trying to figure out when to work/when I should work.
- You can tell where are girl is from from her/by the way she ...
- Film from the back/from behind so that we can see her back an d the guy talking to her.

Thank you