Definitely uncomfortable, mine wasn't painful but I tend to have a higher pain tolerance. To put it bluntly, you're literally just getting a finger shoved up your vagina and rubbed around your cervix so they can check if its open/how open it is, how soft it is, etc. Every one is different, too. So if your cervix is farther back it may be even more uncomfortable for them to get up there.. but it is relatively quick I think they start at 36 weeks? but you can always deny them, too!
Had my 36 week appointment today and I declined the cervix check. If there's no medical reasons for it you don't have to do it. I saw someone who was not my usual provider because he was booked, so when she asked about the cervical check I asked her if she had small hands, because the one time someone other than my OB tried to do the cervical check she had difficulty reaching my cervix and it was very uncomfortable 😵
I found cervical checks uncomfortable and slightly painful but it is over quickly so manageable. Comparing it to what is to come with birth, the cervical checks are easy. This is my second baby and I think I am more dreading birth than I was with my first because I know what to expect this time. Being naive with the first is almost a good thing 🤭 They broke my water in the hospital so it didn't happen naturally. Was not painful and just lots of water with continual leaking (doesn't just all come out at once)