There are many causes of arch pain but the majority of them include either acute or chronic injury to the soft tissue of the foot.
The foot is made up of 4 layers of muscles, surrounded by an envelope called the fascia. Between these layers run nerves and blood vessels. Any of these structures may be injured and contribute to pain.
A common cause of injury to these structures is an abnormal foot posture, often where the foot excessively roll inwards placing an excessive amount of strain on the supportive structures of the foot. Overuse of some muscles of the foot may also be a factor as they can radiate pain along the arch of the foot, this is known as myofascial pain.