I am 52 yrs, 5ft 4in and weigh 220, I wear a 42DDD. I want to know what are the criteria for Medicaid to pay?

A discussion in person after a thorough evaluation can determine if your insurance will cover your surgery. SInce you have medicaid you will have to go to a medicaid provider.

Based on your description you may be a good candidate for breast reduction surgery; it may be in your best interests to drop weight first. Reaching your long-term stable weight prior to undergoing breast reduction surgery will help minimize the risks associated with the procedure and help minimize the chances that further surgery will be necessary in the event of future weight fluctuation.
Unfortunately,  online consultants will not be able to definitively state whether  any specific “insurance” including Medicaid will cover your  procedure. You will need to check with board-certified plastic surgeons in your area  and ask to see doctors in consultation ( who still work with Medicaid).
  Undoubtably there will be some some “hoops” to jump through. The more documentation you have (for example, from your primary care doctor, physical therapist, chiropractor etc.) the better when it comes to obtaining insurance “authorization” for the procedure.
This documentation and letter/pictures from your plastic surgeon will help you obtain authorization.  
Good luck with your  goals;  breast reduction surgery tends to be one of the most patient pleasing operations we perform.

I think the best approach here would be to find a Board Certified Plastic Surgeon that accepts Medicaid.  Then give your surgeon an honest account of your symptoms.  Your surgeon will ask you all necessary questions to decide if you area  safe and appropriate candidate to benefit from breast reduction.