Who to contact for a leaking window?

My husband and I are both first time homeowners. We just moved into our new home, built in '97.

When we removed the blinds that came with the place, water started to leak through the screw holes. We only noticed after a puddle formed. After removing the wood frame at the head of the window, we noticed the wood and drywall were wet and soft on the left side. This window is located in our bedroom, directly under the attic. We inspected the attic and it was all dry but because the water leaking above the window came from the exterior side of the plastic, not sure we would see much.

From a previous post on here, we think it could be an ice dam. What kind of specialist do we contact for this? I am guessing a roof expert? But if it's walls, who fixes walls?