There are many reasons why you might wake up feeling dizzy and with a sore back. It might be that you did not drink enough water before going to bed, or that you slept in an awkward position which caused your back to become stiff. To combat this, try drinking some fluids before falling asleep and refrain from shifting your weight onto alternate sides during the night. Moreover stretching gently upon waking up can help loosen any tight muscles. If none of these solutions work then it would probably be wise to consult a orthopedist.