In flat foot the inside arch of foot is lost. this causes bearing of more load and stress on muscles and bones of inside the foot then their usual capacity. it causes pain on standing & walking. in advance stages due to swelling of muscles and soft tissue, pain may occurs while resting . anti-inflammatory analgesic such as ibuprofen,icing and wearing of medial shoe raise (commercially easily available) inside the shoes while walking will give relief in pain and other symptoms. she raise will make artificial curve of foot and distribute the load accordingly. Hope this helps. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions. Wishing you good health.