Helena's words ring true here, Casper hated me for about six months when he first came to live with us.
Like Pickles, Casper was not given much attention for many years before he came to us and distrusted men because of how he was treated.
I eventually gained his trust and he no longer made me bleed when biting me. Now he reckons that I am better than Margaret at teasing out pin feathers around his neck and on his face so he climbs onto my lap and with his beak grabs a finger which may have been typing an important email to a customer and insists it is put to better use. We all three have a great relationship and unlike some birds he divides his time between the two of us rather than being a "one person bird".
So keep chatting to Pickles, explaining what you are doing like you would to an inquisitive child and hopefully he will become more interactive.
Like children, you can't force them to do something, you have to make them think that it was their idea in the first place.