You've already gotten sound advice about getting checked medically. I would suggest a leg length x-ray on your legs, maybe a scoli x-ray for your back at the same time. It will tell the whole story in just a few pics. It will show where exactly the length discrepancy is so it can be properly handled. IT can twist your pelvis to one side a bit, twist your spine a bit, lower or raise a shoulder, etc. It's not always about a shim in the shoe kind of fix. Actually, it's rarely a shim in the shoe kind of fix as far as riding on the bike. Or, as Knot can attest to, sometimes things just pull themselves one way or the other and you need to rebalance that.

For me, I have a shorter left tib/fib due to being hit by a car but my femur on the right is slightly shorter compared to the left femur from birth. So, while my left leg is overall shorter, when I'm over the pedals, my right femur is shorter. It makes me want to twist my pelvis towards that side, but when my foot is in the down stroke, my left whole side is shorter, making me want to rock that way. No professional bike fitter in the world will be able to fix that without the proper measurements from a good ortho xray series. Many of us fall into this category, one femur is longer on one side while the tib/fib is longer on the other.

I remember reading a thread in here, maybe a year or two ago, where you can get custom crank arm adjustment thingies made. They study your leg measurements and how you pedal and make something that attaches between the pedal and crank arm, or something like that. It can account for one leg being overall longer but the other side having a shorter femur, or any combination... It's hard to describe with out the pics.

Any of you who've been on here for years remember that? I don't have time for the search right now as I'm about to head out the door. But, I know it's here. Whoever it was that did it, loved it and it really helped them on the bike. I really thought of doing it at the time but then life went in another direction for a while.