What pedals said is the number one culprit.
If all your weight/momentum is going to the offside, your bat is going against the tide and things are complicated further if you have to play around your front pad.
Some video of you batting will be more helpful. But as a starting point, stand tall. Move your front foot down the pitch rather than across it. ie, draw a line between leg stump at your end, and the corresponding stump at the other end (will be off stump if you were to bat at the other end) try and put your front pad on this line (or even leg side of it) and then play the shot, should be easier.