Running, hit bottom of foot on curb edge. severe pain. ran today. foot gave out on me. saw dr in urgent care said nothing. pain to walk and stand ?

Possible Fracture: Sounds like it could be a contusion or acute plantar fasciitis. If an x-ray was done at the urgent care center, then a fracture would have been determined. If not, go get one. I had a patient recently who fractured his foot on the edge of a stair. Meanwhile, apply ice/cold pack 2-3 times per day for 30 minutes at a time, and keep the foot elevated. MRI might be needed if there's no improvement.