The pain in the inner arch of the foot is considered to be related to physiological factors, plantar fasciitis, localized nerve entrapment, flat feet, and so on. 1. Physiological factors: Pain and swelling can occur on the bottom of the foot due to prolonged walking, prolonged standing, or muscle strain from strenuous physical activities, resulting in pain on the inner arch of the foot. 2. Plantar fasciitis: generally caused by prolonged standing and walking, or frequent running and jumping. The plantar fascia is often stretched, and with the prolongation of time, it is easy to have localized tearing of the fascia, causing chronic aseptic inflammation of the fascia. 3. Local nerve compression: If there are muscle spasms in the arch of the foot, osteophytes, tumors, etc., it will compress the sensory nerves and produce pain. 4. Flat feet: congenital flat feet or secondary flat feet caused by trauma, etc., can also lead to medial nerve compression due to arch collapse, thus causing arch pain. Pain in the medial arch of the foot may also be related to other causes, and it is recommended to consult a doctor for relevant examinations in a timely manner to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.