Is it normal to be jacked without working out / lifting weights?

Over the past few years, I noticed that I started to go from being some-what smallish in strength into a very built-looking teenage. The thing is, I didn't do anything that would cause it. I did not have any sort of routine that I would workout on a daily basis, a high-protein diet that would make me grow muscles easier, or take any supplements that would help me. In fact, I ate, and still do eat quite a bit of fatty and sugary foods and is considered by some (including my parents) to be kinda lazy.

At first, I didn't think much of it but people started to say how jacked I was and making comments about it. They asked if i worked out or not and I always said no and that lead to them giving me a weird look. More recently these comments have increased with people telling me how strong I look and how much I have changed since I was in 8th grade. Even my doctor appeared surprised when he asked if I worked out or not and I said no.

The most that I do for being "in shape" is running (3-5 miles every other day) and I also play soccer all year. I doubt that just those two things would make me look built to the point that people would compliment/make comments about it (including classmates in high school).

So, what I would like to know is: Am I normal?