i used to go see a physio regularly, good bloke too, worked with the british olympic team...
anyway, crack was i used to get a touch a sciatica, started working on roofs and just continued, got it rendering, then just skimming..
so i'd go see the bloke, he'd stand me up and make me wave my arms about a bit whilst looking at my back muscles (or arse, whichever turns you on :RpS_laugh

then he'd put his finger on the exact areas where the pain was, shoulders, middle of back and side of hips etc...
told me flat feet didnt help, and the fact that ive cracked a t11 vertabrae in a motor wreck years ago..
fingernails in the sides of the knees, legs bent all out of shape, knots worked out etc... painful at the time but it eased up in the morning...
gave me a tip about laying on my back with my calves on the settee for half an hour.... that does help...
then i come across this stretching excercise on the net, never had bad sciatica since... and not been back to the physio either..
first sign of the merest twinge, hot bath, 2 beers, 2 ibufrofen and do the stretches in the bath... job done, immediate result...
its all connected, from your heels to the back of your head....
physio told me of a footballer complaining of headaches....
turns out he had an achilles heel problem....