Conversation so far:
When was Wish You Were Here released?
Most of Wish You Were Here premiered on 5 July 1975, at an open-air music festival at Knebworth.
Released in September.
Which album was it on?
their ninth studio album, Wish You Were Here.
Did they go on tour?
CANNOTANSWER.
Did they have any problems when producing this album?
Initially, they found it difficult to compose new material; the success of The Dark Side of the Moon had left Pink Floyd physically and emotionally drained.

Question: Why were they having trouble?
Self-contained rewrite: Why was Pink Floyd having trouble with their Wish You Were Here album?