Ok it all started like 2 or 3 weeks ago and I had like a couple red bumps on my forearm, they didn't itch or anything because I thought it was some misqutoe bites that were fading and now the bumps have spreas all over my inner forearm on both arms and there are a little on both of my uppers arms and little on my chest and stomache. The bumps don't itch or anything there not irritating at all

could just be heat rash which you can get from sweating and it doesnt always go away immidiatly..
or it may be an allergy?
if it doesnt go then seek help from your docter.