After a couple weeks with a program, soreness should mostly disappear. You say you have class on tues/thurs? in that case, you might try doing 2 full body workouts a week, friday and monday or something like that. You will be sore for a few weeks but in the long term that will mostly go away and you'll appreciate the benefits of lifting. Also, the flexibility loss you speak of is (hopefully) from the muscle soreness, so that should disappear, too. Remember that lifting through a full range of motion will maintain the flexibility of your muscles.