In reply to Taurig: Try different lacing techniques whilst not on the hill as it could be something to do with the lacing system you use. It may sound daft but i used to tie my laces too tight and completely mess my feet up, but with missing out one of the loops my feet are much better on long distance winter walks.
Also I have a really ballerina-esqe instep! Its ridiculous and with different insoles it really made a difference, although I went to a good running shop and paid for someone to check over my feet and recommend good insoles. They cost me £50 but they are probably one of the best items I've bought. They take a while to adjust too, but make the difference after a week or two of solid use.
Hope the above helps or at least gives you some options to consider.