A few months ago I experienced bad pain on the bottom of my left heel making
it difficult to walk.  A doctor couldn't feel anything abnormal.  He suggested
donut heel pads.

I now notice that the source of the pain is near the lower-left hip.  If I sit
or lay wrong it causes the foot pain when I get up.  Riding a bicycle seems to
subdue the pain after I get off.  But the pain eventually comes back, though
not as strong as first, but I can feel maybe muscle or tendon slippage(?) that
runs through the back-knee area.

So I'm wondering what might be wrong.  I suspect a small hernia somewhere.  I
had an inguinal many years ago that was fixed.  

What should I suggest to the doctor?  Someone scheduled me to see a podiatrist
soon.  I'm not sure that podiatry is what is involved.