I have been experiencing lower right back pain for 5 days. yesterday, i noticed a small bumpy rash in the same area of my back. what could this be?

Possibly shingles: It is possible that you have something called herpes zoster, especially if it is painful and there are blisters. It is commonly known as shingles. When you were younger you probably had chickenpox and the virus that causes this rests in a nerve in your spine, and comes out on one side of your body. There is a medication to take so it will resolve more quickly but.It may be too late for it to help.