Chronic, undiagnosed leg pain?

[AlexShee]

Hi. I'm an 18 year old female, and I've been having pain in my entire right leg, hip, and some pain in my lower back for about three years now. I took physical therapy for a slight leg deformation when I was a baby- apparently my foot turned in a lot.
The pain moves around in my leg. Sometimes it only hurts in one spot, like my ankle, and other times my entire leg is sore. The worst pain I have is in the muscle right outside my shin. It's a burning, stabbing sort of pain that never really goes away and worsens when I walk, run, or even stand for at least 15 minutes. My upper calf muscle(s?) were hurting the other day out of the blue, I woke up with it and it didn't go away. It felt like normal muscle strain, but I'm positive that I didn't do anything to cause it.
My knee stiffens when I sit for long periods of time, and my hip occasionally hurts when I put weight on it. Once again, I don't know why. I've had x-rays done and there's nothing wrong with my bone structure.
Sometimes, my lower leg and my foot will tingle like my blood flow's been cut off, but it only happens when I'm standing. My Achilles tendon hurts at times when I walk/run, and sometimes my inner thigh muscle hurts too.
The pain is triggered sometimes, but other times it just appears. No one can figure out what's causing it and it's really getting annoying. The pain has never been really debilitating aside from the one beside my shin, but it affects me on a daily basis.
Any sort of ideas as to what it could be can help. Thanks.