The reason you would chew a pill instead of swallowing it is because when you chew it, you break it into small enough bits to dissolve in your spit and be absorbed through the inside of your cheek and enter your bloodstream immediately and get the effect faster! If you swallow it, it has to be dissolved by your stomach acid and most pills have coatings on them so they dissolve slowly and get absorbed through the stomach lining so the effects start later.
DUH.