Some county bar associations offer pro bono services, but Prince George's County Bar Association does not. Their website does have a list of organizations that provide pro bono lawyers, but the source below (CourtReference Guide to Maryland Courts - Legal Aid and Lawyer Referral) has a better list.
Click the link and you'll get a list of links to legal aid organizations. Most require you to be below a certain income level. Look for links that mention "free and low-cost legal assistance" or "find civil legal help" or "legal aid" or "volunteer lawyers". Most of the linked websites will allow to search by location, e.g. PG County or your city.
Great outlook. A number of med/mal law firms look for MD's to bolster their firm resume. YOu have a better understanding of the subject matter, and much more experience with "standard of care" so having an MD and some years of experience should make you extremely marketable.
FYI, another legal area that recruits those with MD's is Intellectual Property law, especially patent law. Pharmaceutical litigation and patenting is an extremely complex field that requires knowledge of the science behind the product, so you would be pretty marketable in that regard as well.