2004 Vauxhall Astra noisy cams

Noises problem
2004 Vauxhall Astra Two Wheel Drive 75000 miles

hi,have noisy ticking on astra club,recently serviced, and have topped up oil level, have been told its the cams, is it a major job to change,or any advice on cams,also if it has to go to a garage what sought of money are we talking about appox, or any advice on stopping the loud ticking, many thanks