I was down the shore & was walking a lot, only in sneakers. pain started a couple days ago on middle bottom of foot. feels like i over stretched something. pain is worse when foot is flexed. pain on right side of ankle as well. i can barely walk?

Use warm soaks and take Ibuprofen. You might have plantar fasciitis. Also pl see a podiatrist. Hope you feel better.

Pain in the bottom of the arch I would think plantar fasciitis. However, when you include the other symptoms you are not considering plantar fasciitis. See if you can make a circle with your foot and comparing it with your other foot. If there is a limitation in your motion then I would consider a subluxation of a cuboid bone. Pain is usually associated on the dorsolateral aspect of the foot.