This was deffinatly a lucid dream. Sounds like a "natural" DILD -- one in which you knew you were dreaming without doing a RC.

A lucid dream is just a dream in which you know you are dreaming. How you arrive at this conclusion is unimportant.

I sometimes feel my muscles aching while I try to fly or do other "physical" things in my dreams (lucid or not). At times I even think "But I'm dreaming. Why do I feel tired?" Sometimes that ends the sensation, other times not.

Good job on the lucid dream!