Go see the doctor again. I don't know that if you've thought about it but the pain killers do cause constipation for ppl who take them normally.
1 of the Withdrawal symptoms of not taking painkillers is diarreah and it can last several days after you stop taking them.
Have you tried to NOT take the pain meds for a week and see what happens? Be aware that you can have a physical dependance on the med without being "addicted".
I'd try to get a recommendation to a specialist. If you can't find anyone else, try a gynecological urologist and ask for a recommendation from him or her to the right person. Don't let "my doctors are being unhelpful" be your last comment on the subject. You don't want to be on painkillers the rest of your life, do you? Can you imagine the danger? I'd even threaten a malpractice suit if it helps you get to the specialist you need to repair the problems.