Your question is similar to, "why are some people creative?" I don't know. Some people just are.
As for the tools to make a logo, you need: lots of paper, pencils, colored markers/crayons, a scanner and a program to work with digital images.
You should also understand the difference between bitmap (jpg, bmp, gif) and vector formats (AI, EPS, FH11) and know what a PDF is.
Photoshop is mostly for raster (bitmaps) images. After you learn about formats, you'll know why vectors are superior to bitmaps for logos. So, you need a vector program like Adobe Illustrator or Macromedia Freehand. Personally, I prefer Freehand. Too bad Adobe purchased Macromedia (to get Flash) and shut down Freehand.

You can still find Freehand on eBay.
Then, you brainstorm and come up with some ideas. These ideas are sketched onto paper. Just play with them. After you get a few good ideas, you scan them into your computer and convert them with your vector program. That's where you really need some skill and experience with whatever program you chose.
By the way, if you can't draw, you probably should learn how to do that too. You won't be able to make really good logos if you can only draw stick people.
There are also some devices that will allow you to draw while your images are converted to vectors. A Wacom tablet and the Pulse Smartpen are just two tools that will help you increase your output.
Good Luck
