Extreme Pain in Feet and Legs for months

My twin sister has been diagnosed with Hashimoto and ever since then the pain in her legs has been debilitating. It started in her feet and now it's upto her legs as well. Her thyroid and vitamin levels are allll normal now and yet the pain lingers on. More info -She describes it as tingling and sharp -It gets worse when she walks a lot. More steps more pain -B12, vitamin D, and thyroid levels etc all is normal after meds -Shes complaining that the pain is starting in her palms as well so I'm worried -Its been happening for over 3 months, with short periods of relief but has returned now. -Shes on levothyroxine It's really sad to see her suffer and cry in pain and i don't know what to do- we don't know what's happening and doctors keep telling us "go to gym" or "take more B12" and generic advice like that. Is there a genuine fix for the pain? She's afraid her nerves are slowly dying and constantly in pain unable to even go to college . What treatment or doctor do we even take her to