When we have tension or soreness in the sole of the foot, it's important to address the calf muscles and achilles tendon as well. Too many professionals hyperfocus on the plantar fascia and ignore the treatment of the greater functional network involved.
In shiatsu therapy, we approach anatomy from the perspective of the musculotendinous meridians. These are chains of muscle, tendons, and joints that run longitudinally along the body. Each chain of tension is involved in specific actions, such as twisting, side bending, or activities like running or lifting something heavy. These compound movements are not the result of one muscle action but the synergistic action of all of the structures in a meridian.
So, when we have abnormal tension or pain somewhere like the sole of the foot, working on the calf and achilles tendon, as well as the sole of the foot, will make a bigger impact. There's a lot more you can do that's just scratching the surface.
Check out the video explaining this and demonstrating the techniques you can use to work on this functional chain yourself. You can click here, or click the image in this post to see the video.