sounds like most of your power is coming from the down stroke only. You should be pulling up on the up stroke and sweeping back at the bottom and pushing forward at the top of your pedaling stroke. Ask your BF about it.

When you learn to apply power on full circle, you'll find that things are lot easier and easier on your quads.

And if your quads feel sore after a ride, sit down and use a roller to massage out the built up lactate in your leg. This will help you recover faster. And feel better too!

You can buy a roller from a cycling shop and if you can't find it, you can always improvise.