Aching or stiff/tight pain in the lower backside of the leg.
Most cases of calf pain are the result of improper alignment at the feet. In this case, a strain could develop because the calves are being used to compensate for the lack of proper support.
The highlighted muscle (Tibialis Posterior Muscle) connects from the bottom of the arch to the calf. When the arch is not supported properly and drops lower to the ground, the calf has to work harder. This can put a strain on the muscle or the calf because of the constant tension and pulling.