This is what I found from a breif google search.
"On February 12, 2016, the Patriot Care Corp. was approved by Governor Charlie Baker’s Administration, allowing retails sales of marijuana to registered qualifying patients and personal caregivers"
"Patients in Massachusetts diagnosed with one of the following severe, debilitating, or life-threatening medical conditions, are afforded legal protection under the Massachusetts Medical Marijuana law:
Cancer, glaucoma, positive status for human immunodeficiency virus (HIV) / acquired immune deficiency syndrome (AIDS), hepatitis C, amyotrophic lateral sclerosis (ALS), Crohn’s disease, Parkinson’s disease, multiple sclerosis, and other conditions as determined in writing by a qualifying patient’s physician."
The above information was copied from: https://www.marijuanadoctors.com/
I believe The Holistic Center in Boston, MA could be a good starting point to obtain a card.