I need a doctor to answer this...?

When you don't have any abnormalities in the joints or bones, that means the problems is occurring in the muscles, tendons, or ligaments. Possibly, the pain you are having is caused by overly tight tendons and muscles, and the problem you are describing looks like the problem could possibly originate in your Iliotibial band. This is the main tendon that runs from the top of the hip bone down toward the bottom of the thigh. A tight Iliotibial band can cause your leg to rotate at the hip joint and then pull against all your other muscles. It can also cause a person to walk pigeon toed. This is a common problem with people that have long legs, but it can happen with any sort of body type. You can test this idea out on your own by trying the stretches at the first link. There is more info for fixing back pain at the second link

If you think the cause might be tightness, it would be a good idea to pursue two routes simultaneously: make an appointment with a physical therapist and make another appointment with a chiropractor.

I'm no doctor--just going to throw that out there--but you should take some Advil for your pain. If it's unbearable, you need to straight up tell the doctor that something needs to be done.