All stars are suns. Our sun is a star (called Sol).
The sun's "warmth" isn't actual heat, but radiation. The Sun is constantly emitting massive amounts of radiation (even light is a form of radiation). That means the light you see from distant stars is radiation emitted from that star that made it all the way to your eyes. So in actuality, that star's "warmth" made it all the way from there to here. The farthest star we can see with our naked eye is over 16,000 light-years away. When we see the the "warmth" (light) of that star, that light left that star over 16,000 years ago (now that's some old light).
All galaxies have stars. That's why we can see them. In fact, a galaxy is just a huge collection of gas, dust and stars (held together by gravity). At the center of every galaxy is a black hole. Its possible that the gravitational forces of that black hole help to hold the galaxy together. Not all stars are like pours (the sun). At 864,000 miles across, our sun is "average" sized. There are stars out there that are 1700 times bigger than our sun (red giants), and some that are just a bit bigger than Jupiter (red dwarfs). Neutron stars (the core of a star that exploded) are a little over 12 miles in diameter. However, most of their radiation is outside the visible spectrum.
