I have plantar fasciitis & metatarsalgia, but the entire ankle & foot hurts now even non weight bearing. Could MRI show anything?

Possible. Your question as stated is answered with a yes of course. An MRI may be a revealing test for multiple issues in your foot and ankle. BUT, an MRI is not always the magic answer. You need to follow-up with your foot specialist/doctor and tell them of your new issues/symptoms and get an examination to see what, if any further testing is needed. Best wishes.