I Have Constant Pain In My Hip. Range No Pain

i have constant pain in my hip. range no pain sitting or laying down. the pain comes on when i walk ,and the longer i walk the stronger the pain in a long walk of 100 yards or longer .the pain can get to a range of 6-8.i am told from doctors the pain originates under my vertabra at hip hight. i have seen many docters and have had many procedures also had an mri with no resolution.can you help.