When lying on back in bed and trying to sleep crackling/moaning type noise coming from chest or throat, i turn onto side and noise stops. what is it?

Cardiac eval: You should see a cardiologist for a potential cardiac source. However, your symptoms can be attributed to many things. You would need a Chest x-ray, routine blood work, and a thorough physical exam/history. After that, you may need further testing depending on the results.

Hmmm?: Possibly chest congestion, where mucus in your airways is causing a noise when it rests in a certain way in the lying position, and then when you move positions, the mucus moves too thus causing a more patent airway in that place and allowing air to flow more readily without making the noise you hear. Get an eval if it persists. Best wishes.