posterior tibial tendonitis

I was diagnosed with posterior tibial tendonitis and overpronation. I have pain in my right arch when I take my first few steps after resting. Then I can walk pain free. I have been wearing a small stretch ankle brace and wearing open toed sandals because I also have toenail fungus. Should I wear a better brace for a while and do any kind of foot exercises and stretches? I've seen intertnet videos about it but not sure if the exercises are safe.