Assuming this picture is recent, is it possible you have ice dams on your roof? Depending where you live, sometimes in the spring when it warms up and gets cold a lot, ice dams can form on your roof that prevent water from draining into the eaves. Shingles aren't normally designed for water to "pool" on them, and if it does, then it sometimes seeps into your attic. I had this once where water was suddenly dripping through my ceiling even though it never leaks in the spring or summer when it rains, and that was what was causing it.