Red Spots on Son's Skin

Is it possible they are flea bites?

Where are the marks on him?

Flea bites can appear anywhere on the body....but tend to show up on trunk and belly around waist line...and then on legs.

It is a shot in the dark....that is my grand guess without seeing them though.

They tend to be flat or slightly raise....my kids dont itch with them and they normally disappear within 12 to 24 hours.

I say though ALWAYS air on the side of caution. If you think it could be a reaction to the shots maybe he should go get checked out....always better to be safe rather then sorry when it is something worse.

eczema? with my son it's slightly raised red patches, or some just red patches, that sometimes seem to itch and other times not.

Our pediatrician always gave us informational sheets regarding each vaccine which included possible reactions and what to look for. If your Dr. didn't, I would Google each one.
The rash could have been caused by a number of things. A change in detergent or fabric softeners has caused my son to get itchy rashes.
Also, if I'm not mistaken, kids can get the chicken pox even after having the vaccine but the severity will be less if they have had the vaccine.
I would try to take him in and have it checked.

Well if it's just recently started and his shots were 2 weeks ago it's not a reaction to the shots. Blotchy sounds like hives. My oldest had roseola that rash is flat and lacey and you get pretty sick with roseola (high fever 103+, tired, cold like symptoms, etc)