i have had chronic pain in my lower left abdomen for the past 12 years with no diagnosis help!

I have been to several doctors from Ohio to California, I have had pelvic exams, ultrasounds, cat scans, and MRIs with no findings.  The pain in now recently moving across to the right side of my lower abdomen and upward to the middle of my left abdomen.  I have just lived with the pain on my lower left side for the past 12 years but (figuring it didn't kill me yet - lol) this recent development of extension of the pain really has me concerned so I went back AGAIN to the doctor and AGAIN no findings.  Im sick of being in pain every minute of every hour of every day - please help!! Any information or any referral would be greatly appreciated!