A plumber will typically clear the line, then run a camera to find the cause and location of the damage. The video shows whether the problem is roots, a break, or a sag, and how deep and far from the house it sits.
Repair options range from replacing a short section to relining or replacing the whole run. A plumber with a Massachusetts license should file the plumbing permit with the Hull Building Department, which takes plumbing applications online, and arrange the inspection with the part-time plumbing inspector.
Before any digging, walk the route with the plumber and point out fences, walkways, plantings, or a driveway in the way. Ask who restores them and whether that's in the price.