The bumps color are red and there not that big like a inch long and 3 centimeters wide.

I'd say an inch is pretty big. Lumps can be any one of a number of things, from bug bites to cysts or tumors.

How long have they been there and have they been growing in size rapidly, or over the course of a few weeks/months?

I have to agree with Shaz here, those sound pretty big. Seeing as we can't see them, we really couldn't give you an answer. Too many possibilities.