I came home tonight and found summons under my door. I live in massachusetts is this legal. do I have to go

If you have refused personal summons the judge can order service by posting the summons to your door. It is legal and you must appear when ordered to.

Not all summonses have to be served in hand.

Leaving the summons in the door is considered proper service in Massachusetts. Separate and apart from that, I always advise everyone to contact the court immediately if you think you might possibly have to go to court. It's never a good idea to assume you don't have to go.