My feet burn off and on for 2 months now and my left big toe has been numb long what can cause this?

Many reasons: Bilateral nerve pinching at ankle (tarsal tunnel syndrome), plantar fasciitis, polyneuropathy such as diabetes, small fibre neuropathy perhaps. Visit a podiatrist or an orthopedic foot specialist and get evaluated.

Nerve related: Can be a form of neuropathy or a pinched, compressed nerve higher up in ankle, leg or back, see podiatrist for evaluation.

Nerve: U agree with dr machamic, and also consider sciatica and vascular insufficiency.