English spelling is crazy. There's no sense to it. There aren't many rules, and the rules aren't reliable. In most cases, what is happening is that the spelling preserves the way the word really was pronounced many hundreds of years ago. In the word "adore," d-o-r-e has the exactly the same sound as "door." In the word "dormouse," d-o-r has exactly the same sound. The two different words "pore" and "pour" rhyme perfectly with "door," and, depending on regional or individual pronunciation, so does "poor." "Soar" (glide through the air) and "sore" (feeling pain) are pronounced the same way. It's just crazy.