My son has red bumps big and small all over his body some on his face and a few on his head. what could it be? no itching and no fever but very cranky

Probably viral rash: Viral exanthems usually stay on a few days. Should he develops drastic change in his general condition, have him checked.

Could be simple rash: This could be something as simple as 'heat rash' or acne although acne would be my second consideration. I would recommend that you see your pediatrician to verify exactly what this is.