What is causing this pain in my left leg and tingling/numbness in my arms/hands?

Neuropathy ?: Neuropathy is a comon cause of tingling and numbness to the hands and feet, specially if diabetes is present . Duration of symptoms is also very important , as well as family history. Neuro-degenerative disorders must be excluded, if history or physical exam is suggestive.. Vitamin and nutritional deficencies is a rare cause, but possible if an enteropathy is present, or bariatric surgery was done.