Replying to Intense pain in balls of feet! +k for help

I brought a pair of Dalbello Voodoos about a month ago, had them properly fitted and all by my local ski shop with footbeds etc. Ive used them about 6 times and every time after about an hour I get a real intense pain in the balls of my feet! I try to ignore it as long as I can but eventually I have to sit down somewhere and loosen them off to relieve the pain. I'm really needing ideas on whats causing this!