The reason I suggested that you explore tarsal tunnel entrapment neuropathy is because the symptoms that you are reporting are very common in this type of neuropathy. The fact that the symptoms occurred 6 months after the achilles rupture raises this possibility. The tarsal tunnel is in the lower ankle and is similar to the carpal tunnel in the wrist. The injury may have cause changes in gate, increased pronation or other aberrations in walking that put undue pressure on the tarsal tunnel resulting in increased inflammation in the area. This inflammation can cause neuropathy. I would consult an orthepedic foot specialist. Sometimes something as simple as an custom-footed orthotic can relieve some of the discomfort