Try rolling over to your side first, and pushing yourself up with one arm, while bracing a pillow against your scar with the other hand. And swing your legs out at the same time. Then stand up.
yes that, I did not experience pain like that (I was in to a standard queen size bed day after cs) but everyone has diff pain threhold. Ask MW to hve a look at wound and check for infection or as others have suggested tight stich.
You dont want to take the strong drugs fir too long due to risk of constipation.

By day 5 most woman are on panadol, voltaran and tramadol.

Hope you are better soon you have had a tough pregnancy.