Ball pythons are very shy snakes. They thrive in smaller enclosures. They spend 90% of their time hiding, so the constant roaming and exploring is actually a sign of stress.
How are you measuring temps (what kind of thermometers) and controlling your heat source (what kind of thermostat or dimmer)?
If you look at a 55g, you will notice that it is super tall, and ball pythons are ground dwelling snakes. They will only use the bottom 12" of the tank, so you are basically heating 20 gallons that will never be used by the snake.