Knee pain bike riding?

[colttostallion]

I learned how to ride a bike about four months ago and until now have been riding about once a week. It was uncomfortable/painful for my calves whenever I rode, but I mostly figured it was due to using muscles I wasn't used to using. When I began to ride more often recently to get to work I raised the seat so I can only reach the ground with the tips of my toes standing. However it still causes pain in my calves and now in my knees. A friend told me that I should be able to almost fully extend my leg on the down stroke of the pedal, which I would have to raise the bike seat a few more inches to achieve, but I'm already on just the tips of my toes and having just learned how to ride am concerned about balance.