The fact that the pain subsides while running and comes back later when things stiffen, shows there is a heavy muscular component to your pain. First off, I would say that the types of events you are competing in aren't helping any. When things get this bad (especially when you are new to running), you need to stick with a gentler regimen and not tempt fate.

I don't think you have a problem with any particular muscle. I think you have a problem with a lot of them, and their stiffness only increases the workload and vulnerability of other muscles working in concert or in opposition. We classify groups of muscles as agonists, antagonists, and synergists. There is a lot of cooperation and redundancy to most movements. When one drops out of the mix due to overuse, the others have to work harder. When they resist movement, the muscle(s) on the opposite side of the joint(s) must also work harder.

Muscles move joints, and often attach very close to the joint itself. The pain they produce is often mistaken for pain in the actual joint. When the muscles warm up and/or relax, the joint pain often disappears, showing the joint itself is not the problem. When they stiffen later after a workout, pain - even after limited movement - is not unusual.

Needing a cane suggests quad failure, which can be in response to knee pain alone. The amount of contraction force available to a muscle depends on the health of surrounding tissue, as well as the health of the muscle tissue itself.. You are programmed to reduce contraction force in prime movers when either primary or secondary tissues are at risk. Happens to the best of us, all the time.

For now, forget beating yourself up in favor of a little more R&R. Keep moving though, so things continue to work the way you want them to after you heal. In addition to the circulatory benefits of light activity, mobility of your lymphatic system can be obtained with light massage to the extremities. The lymphatic system is vital to tissue recovery and removal of waste. Foam-rolling the legs downward toward the feet is counter to proper lymphatic flow, which is controlled by valves in the lymphatic vessels. If you foam roll, as suggested by many in the RW forum, don't make the typical mistake of rolling down because it looks easier. Roll upward to enhance lymphatic flow. There is no heart to circulate lymph, only movement and external pressure. Movement always helps courtesy of the valves, but external pressure must be done right. The valves are there to prevent pooling of fluids in your extremities as you run. Don't fight them. Work with them, or risk damage.

If there are knots in some of the muscles that are behind the splinting effect, disabling them may require deeper work with an elbow, reinforced thumb, or other blunt object. Avoid invading the space behind your knee as much as possible. Concentrate on the upper and lateral calves, hamstrings and lower (medial and lateral) quads. Relaxing each section will contribute to the recovery of the others, until you have relaxed them all. After the damage is undone, continued training will have a beneficial effect, but you run the risk of making things worse if you do not take these steps in the proper order.

Regarding one of the posts in the RW forum, the "shrink wrap" explanation of fascial compartments was probably invented by a therapist to explain what they were trying to accomplish. It's a bit deceiving, if not naive, to suggest there is a whole lot of shrinking going on. What usually happens is that muscles outgrow their fascial compartments when they develop too quickly or there is internal swelling, resulting in something called compartment syndrome, a painful and often dangerous condition. If it was really that easy for someone to stretch the tough fascia that contains our powerful muscles, the muscles would be able to stretch it all by themselves, and there would be no such thing as compartment syndrome. Normally, gradual expansion is exactly what happens over time when we develop our muscles at a normal pace. Too much, too fast, too soon, and compartmental pressure can build, especially due to internal injury that attends overuse.

In your case it is more likely that you have a widening pain referral syndrome as a result of the rapid change from light training to extreme endurance events. However short in duration they may be, the effect on unprepared muscles, ligaments, tendons, and bursa, can be as dramatic as the events themselves. First to go should be your tenderfoot muscles, which can and do radiate pain throughout the area around the joints they move, increasingly as they accumulate microscopic damage. They will tend to stiffen or "splint" long before the damage becomes major, causing you to limit your activity by design. Honor this effect, and cut back on the intense training while optimizing your chances of recovery through adequate rest, good nutrition/hydration, gentle exercise to model the repair, and a form of massage that not only soothes and circulates, but directly targets dysfunctional portions of muscle.

Let me know if your need any tips on self-massage techniques. Several examples can be found on the web, but they are not all good, especially the ones involving a foam roller. Eventually, as you strengthen, you will need less of this support as your muscles strengthen to resist damage, your technique improves, and your routine allows for enough recovery to keep up with your training.

Just checking back a week out, but the way it usually works in LLDs is a long-leg knee problem from not being able to plant without lifting, and a short-leg achilles/forefoot pain problem, since that leg has to lift more to stay level. Hip problems can go either way depending on how you compensate.

Regardless, I have tremendous respect for your athletic career and the triumph of human spirit over diversity. You have certainly demonstrated more heroics than most of us are ever called upon to deliver. Nevertheless, I would not be surprised if your best years are ahead when we get this thing under control.

As I recall commenting in another post somewhere, I remember a class where a guy explained that leg-length differences of as little as 1/8" were relevant in clinical practice. When the crudely fitted prosthetic legs of amputees at the VA were adjusted to the exact lengths they were supposed to be, the chronic pains reported began to disappear. I'll bet your chances are even better with the natural equipment you've got.

My take on the rod is that it certainly altered the potential for spinal problems resulting from chronic scoliosis, but I supposed it left everything from your pelvis on down holding the bag. You have shown how tough you are, so I expect you to overcome all of these past problems and re-train like you have a new body. Any luck with home-made or professional orthotic support?