Tightness and pulsation in your back can stem from muscle strain, stress, or poor posture during sleep. This discomfort may intensify when resting on your back, as certain positions can strain your muscles. To alleviate these symptoms, consider gentle stretching, using a supportive mattress, and practicing relaxation techniques. Heat therapy may also help soothe tension. If the issue persists or worsens, I recommend seeking guidance from an orthopedist for a comprehensive evaluation and personalized treatment plan. Your well-being is important, and getting expert advice can be beneficial.