Red rash on 2 and a half years old. Rash is a little bumpy. Slight fever. No pain nor itching....Is it chicken pox?

Different stages. The rash in chicken pox is very itchy and is characterized by having different looking rashes on the skin at the same time. This represents the evolution of the rash over time. So if you look at a person with chicken pox you can see a lesion that is just a red bump next to a lesion that looks like a blister and you may see another lesion that looks like it is crusting over. This happens over days.
Very unlikely. Your child should have had the first set of chicken pox shot already. Chicken pox (varicella) always start on the trunk, initially as raised red bumps. As the rash spreads to periphery (arms and legs), blisters and pustules (blisters with pus-like fluid in it) appear. These rashes cause itching.