malkore is right. make sure you do lots of stretching after a workout( i also do a second set of stretching just before i go to sleep at night).
a gentle walk in the afternoon also helps me when ive done a strenuous workout, it seems to relax my muscles.
my muscles used to feel tight but these days ive been doing cardio daily and no muscle aches to tell of, so your muscles should get used to whatever exercise you are doing and wont ache in a month or so but until then make sure your muscles get good rest,ie dont work them 2days in a row.