Feet. Amazing how much we ignore the two things that have gotten most of us around all our lives. That is until our dogs start to yell at us. What I have learned is that they have been talking to us the whole time. We just aren't listening. Plantar fascititis never occurs over night, but one morning we feel that pain for the first time.
Heel pain occurs because the tension in the calf is so great that it limits the flexibility of your heel. The heel not being able to move the plantar fascia micro-tears from the front of your heel. The pain stops when you finished tearing last night's scar tissue. Repeat for days and weeks until you can't stand it any more.
Solution: stretch your calf and strengthen your shin.