Cat shakes her head a lot

My 6 year old cat had a dental cleaning with 6 extractions about 6 weeks ago. Everything seemed to go well except I notice that she seems to shake her head quite a bit as if there is something in her mouth that is annoying her. It's not constant but she wasn't doing it before the procedure. It's really hard to look in her mouth so before I get someone to sit on her so that I can take a look (won't be popular with her) I thought I'd check to see if this was common.

I was thinking that there might still be a stitch that hasn't absorbed properly. She started doing it almost as soon as she got home from the vet. I just figured the stitches were annoying her but it's been long enough for the stitches to be gone.

She does not seem to be in any pain at all. She is otherwise acting perfectly normal.

Any ideas?

thanks