I agree with Jim that this probably stems from hip dysfunction, and that unless there is a serious structural problem with your foot, an orthotic is only a quick fix.
You describe running at pace for 7 miles of a "mini" (which I will assume is a half-marathon), and run/walking the rest only 11 minutes down from goal, which means you probably pushed those first 7 miles. You mention "slow" runs after your symptoms were problematic, which makes me think your prior runs were not that slow.
A lot of goal-oriented runners train out their race in the belief that a relaxed pace leading up will slow them down in competition. Of course, running at less than potential won't get you to peak performance, but running so the rate of wear-and-tear exceeds the rate of recovery will slow you down even more.
It is evident to me that things have not been healing as fast as you have been tearing them down, so relaxed training is all you should do at this point. To direct your recovery, focus on what may have gone wrong with your hip flexors, which strain much harder when the pace is pushed.
The main hip flexor Iliopsoas muscle starts on the lower spine and attaches to the femur near the groin, and is a frequent source of pain in both locations. Sitting in chairs while driving, working, eating, or relaxing, does not help this muscle which continues to shorten in the seated position.
To restore the rest of your leg to normal function, you need to "open up" the hip, starting with the Iliopsoas ("Psoas") muscle. Feel with your fingers in the groin area where this muscle can be felt flexing as you lift your thigh upward toward the chest. The muscle goes underneath the bowels to the lumbar spine, so for most of its length, it is difficult to reach. There are videos out there describing technique, but your first attempt may find painful spots. See if you can gently rub them out.
Please note there are several muscles involved with hip flexion, but symptoms point to the main flexor Psoas.
Once the hip flexors have relaxed, The thigh should swing normally to and fro with little resistance or pain. I have found it sometimes helpful to set the tone with a gentle stretch by arising from bed, leaving one leg on the bed while the other supports me on the floor. Raising my back upwards gently stretches this muscle. As with all stretches, stretching to the point of pain can be counterproductive.
An example of a similar stretch here...