Well, aching muscles are a good sign that you are working them, and yes, I've discovered all sorts of muscles I didn't know I owned

However you shouldn't overdo it. Your muscles need time to develop, so you should rest them periodically, especially at the beginning. A lot of people overdo it and risk doing themselves an injury.
Mix in more fun stuff with your muscle exercises, have rest days every few days, try not to do so much in one go.
If you overdo it you'll just find that you get sick of it all and your body starts to rebel. Take it slow, and build up what you do gradually.
There's no point rushing, fitness should be a long term, life-long, goal, not just something you do for a few weeks and then give up on because you overdid it.