I went 2 yrs before I was referred to a pain mang. doc simply because they could not figure out why or what exactly was causing the pain persistence does pay off only you know how bad your pain is and don't let anyone try to undermined it if you truly think you need help don't give up until you get it.
I found out after they did a nerve study on me that due to previous surgerys which were very few the had caused perment nerve damage and then finally I was taken seriously but in the mean time I spent over a year and a half in bed so act while you strong and don't let the pain take you over like I did by just accepting that no one is taking your pain for what it is.
I wish you the best of luck. Don't give up no matter how many doctors it takes you will find one that will listen.