1. I have never caught a shiny .. donyou see they are shiny before you catch then or after?
AdaHopper Before. When you click on a Pokemon, if it is shiny loads of stars will appear to indicate that it is shiny.
Outside of events though, shinies are exceptionally rare.
2. What are lucky pokemon?
They cost 50% less stardust to power up, but they can only be obtained via trade (and you can’t determine if a Pokemon will be lucky or not, it just has a chance of turning lucky when traded).
3. I put my blissey in a gym in France whilst on holiday. It's been stuck there for 19 days... how do I get it out?
You can’t! Your Blissey will be returned to you once someone battles the gym and knocks it out, whether that takes days, months or years (and yes, I know someone who lost a Pokemon in a remote gym for the best part of a year!).
That’s why it’s a good idea not to put your best defense Pokemon in gyms you don’t frequent often.