I have a discomfort and pain in my left knee and ankle. i haveflat feet and i also sprained my ankle before. what should ido?

Flat feet: Flat feet can cause ankle pain due to over pronation, this can also cause knee pain from over compensation . Your best bet is to go to a podiatrist who can prescribe or dispense custom orthoses. The orthotics will help you stay in a more neutral position and will help your pain.

Maybe Orthotics.: It sounds like you may have a biomechanical instability in your feet that is passing problems "up the kinetic chain." custom made prescription orthotics, made by a certified lab, under the recommendations of a podiatrist can help tremendously!

Sprain: Flat feet can lead to a host of problems. Orthotics are a huge help - seek the help of a podiatrist to have these made . I use them myself and they really do help . Best of luck.