Hi Matt,
You are in luck I run the London foot pain Clinic and am also a Chiropractor, this has lead me to get a unique insight into how the foot pain and lower pain play a pivotal role.
Some years ago you had a condition called facet syndrome from the lower back. The past management sounds like it only focused short term pain, the brace no doubt cause quite bad atrophy of core muscles due to length of time worn.
The best treatment for facet compression is facet release which can be done by manipulation. Physiotherapist only learn this post grad, if at all, and while some are good it can take years to master. For this i would tend to go to a osteopath or a Chiropractor. This technique has also been recommended by national institute for clinical excellence for chronic lower back pain.
Manipulation will reduce the pain quickerly normally within 3 visits but then you must follow a course of rehab exercise to strengthen backs resolve, through stability issues.
Although I haven't seen you - many people that suffer through chronic lower back pain start to posteriorly tilt pelvic - This would lead to excessive glut tightness and SI joint strain. foam roller on gluts (glut med and piriformis muscle) and SI manipulation combined works exceptionally well here.
The calves very rarely play a role in heel pain at the bottom of heel. and most certainly do not cause pain in front of shin. no doubt you have MTSS combined with some plantar facitis.
The MTSS can be helped with a ankle strap during runs/ long walks combined with daily icing of inside of ankle.
The Plantar Fasciitis or pain on underside of heel is generally caused by over pronation (flat feet). We you assessed for this with a running assessment? e.g. slow mo camera.
frequently we see the slight over pronation on standing assessment with extreme over pronation during running gait. this would cause the P fascia to over stress. This leads to thickening - which once chronic only shock wave therapy has been proved to be successful in release. That been said you can find some free exercises at my website: click here.
Does that help?