Certified Mail-Informed Delivery

Hi,

I saw on my Informed Delivery that I'm getting certified mail from a lawyer's office. To my knowledge, I don't have any reason for a lawyer to contact me (motor vehicle accident, workers' comp, debt). I am a medical professional but I don't practice in the state that the lawyer is in (I only live there). I know everyone will say to wait and see what the lawyer says but my anxiety is through the roof. As lawyers, what are some reasons to send certified mail?