Problems with digitizer is well known on JET and also mine phone went to repair a week ago and now is back and fully working touch screen. I tried many advices before (fridge, digitizer "massage", recalibrating, restarting... nothing helped) only way to solve it is replacing bad digitizer. If your phone is in guarantee then dont wait and take it back to retailer. Other way you can repair it yourself (only if realy manualy and knowing expert) digitizer costs few bucks on ebay, or take it to repair service nearby...