Hello
Welcome to health care magic.
Pain in arch of foot with stifness appearing on rest can be due to inflammation of plantar fascia or simply called as plantar fascitis.It can occur because of excess
stress on muscles or ligaments of foot who already are prone to have plantar fascitis because of
flat foot.
If I were your treating doctor,I recommend,
-Anti inflammatory analgesics like ibuprofen/
naproxen twice a day for couple of days.
-Ice pack local application for 15-20 minutes for 3-4 times a day.
-Muscle stretching and relaxation exercises of foot with the help of physical therapist may give pain relief.
-Avoid triggering factor like ill fitting shoes.Use shoes with proper cushion at arch level and enough space for toes.
If symptoms persist beyond 7 days,visit to orthopaedician for further specific management and ruling out other possibilties of foot pain.
Hope this information helps.
Feel free to ask if any more doubts.