This sounds like eczema (I have it).
YES!
I think so... everytime I break it up my hands itch and small red or skin colored dots come
These are called hot spots call your vet and get some medicine they will go away fast.
Sometimes it does itch.
Chicken poxs if they are red
I have a bump directly behind my ear which is a cyst. They will sometimes grow bigger and if it bothers you, you can get it removed. Sometimes they will be sore when it grows but it often wont bother you.
If you live in the southern US or Carolinas it could be Chigger Bites.
Usually a week
no
Bumps may form after a caterpillar has crawled on the skin. The bumps may go away after 3 to 5 days. If the bumps itch, a good home remedy is to apply any stick deodorant to the affected area when it starts to itch. A person should seek medical attention if the bumps appear in the form of blisters or turn a bright red.
I can speak only on the latter part of your question, the Vicodin. Vicodin is an opiate, and any opiate, even in smaller doses, can affect your histamine receptors and cause hives or itching, little red bumps all over your body that itch something awful.