Hello and thank you for posting. 

I can tell you are very worried about why the procedure was painful, but you should not read anything in to it. It was unfortunately just very uncomfortable for you. 

It is is difficult for me to say why specifically your cervix wasn't opening enough, but that sort of procedure would make it very difficult to relax. Any stress can cause muscles to tense up and make the procedure more difficult and painful to do, similar to a smear. Also a narrow cervix can also be caused by a number of other things like the menopause, infections, previous treatments or traumas. But it does not mean that there is definitely something sinister occurring. 

I've placed here some information on womb biopsies in case it is useful.

Take care Debz, and hopefully you will get your appointment through soon and know more of what is going on. 

Sarah.