This is just a thought and of course a doctor would have to diagnose you,
but I have had those pairs of
red pimples on my chest with a bit of a painful and sensitive sensation (clothing even bothered it to touch). I've also had them on my leg with there was a pattern of skin sensitivity that went along with it; lasted for around 10 days or so. When speaking to my doctor, at a time when it wasn't "active," he said that it could have been a light case of shingles.