Suggest Treatment For Chronic Pain

Hi. Ive been dealing with chronic pain for 8 yrs now eith no diagnosis...Ive been to every dr possible in mn and the mayo clinic three times n nothing has been resolved..I have up goin to the dr due to constant disappointment... but due to a recent car wreck my head has been non stop aching... I cannot live a normal life due to constant pain n in dying need of anyone help or suggestions...im only 23 yrs old n have yet to fulfill my dreams because of the pain... please help me.... thank u..