Lower right back pain and pelvic pain

Hi, I have been having lower back pain for about 2 months now. It bothers me mostly while sitting down. I went to the doctor and she gave me anti-inflammatory medication. It did help but now the pain is back and now have pelvic pain associated with it. I noticed that when I need the restroom, the pain gets worst in my pelvic. I am going to the doctor again this week to let them know. They did tell me that my next step would be x-rays or something. I just wanted to see if any one else has experienced this.