Hello
@peterbells Above the high altar is a statue of St. James. Behind the altar on the right side (when facing the altar) is a small staircase. Climb the stairs and on the top landing you will find yourself directly behind the statue where you can hug it. I believe this staircase is open any time the cathedral is open - even during mass! Near the staircase to the statue is another staircase that leads down to the crypt and the silver box that is said to contain the remains of St. James.
As mentioned by
@Peter Fransiscus as well, the Cathedral Museum and Roof Top tour is wonderful (also a visit to Pilgrim House pilgrimhousesantiago.com) A special place to visit at the end of your pilgrimage, for coffee and conversation in the afternoon with other forum members is Egeria House, the home of S.Yates. Information about her open house times can be found at egeria.house
The Pilgrim Museum in the Praza das Praterias (next to the Cathedral) is also worth a visit.
To really experience a special atmosphere of Santiago, walk the streets at dawn and visit the Cathedral when it first opens in the morning.