I am a 33 year old female that is over weight. i have had pain in my left shoulder, with heaviness and numbness to lower left arm and neck.

Couple points: The pain doesn't necessarily have a thing to do with obesity (most of your weight is below that area). But, http://www.amazon.com/dp/0692496157/ is a guide to overcoming the compulsions/habits/triggers that make us overeat. Pain that goes out in the pathway of a nerve is usually due to a nerve compression. Neck or Thoracic outlet are common spots.