Hello I have a bump on my back like a pimple. And it hurts when I touch it or when I lay down?

It happens. These can be pimples, infected hair follicles or inflamed cysts. When they become painful you can sometimes help them heal with a heating pad that improves blood flow/self healing. If that is no help you may need to have a doc lance it.These are commonly nests of staph or other skin germs.