I have a sore tender spot on my back there is no redness what can it be? I also have lupus

See doctor. Probably unrelated to lupus and if persistent you should get it checked out.
You . You could be dealing with a cystic lesion, lipoma (fat filled lesion) , or even the start of an infection. There is also a type of nodule in people affected lupus that starts under the skin and is very tender to the touch. It is extremely difficult to say with out a more detailed history and physical. My advice is for you to schedule a visit with your primary care provider, dermatologist, and/or rheumatologist for an evaluation and treatment. Good luck.