a 23-year-old fast-food worker presents to your office for evaluation of pain in his feet, especially the heels. he notes that the pain is most intense when he first awakens, then eases up somewhat after walking for a few minutes. by the end of the day, the pain has returned again to its full intensity. he has tried over the counter analgesics without success. he denies fever, chills, trauma, or injury to his feet. on physical examination, he has tenderness upon palpation of the plantar fascia. there are no deformities or joint swelling. what is your most likely diagnosis