Showing loyalty by remaining obedient to Allah Ta'ala

Q: I prayed to Allah that I really wanted something and I made I’m not sure like intention I guess or I said that like I’ll be on my kinda best behaviour or just stay away from sins etc. because I wanted that thing. 

Is this permissible to do? To stay away from sinning so that Allah grants you your dua and gives you what u want? Or does abstaining from sin and doing good have to be solely for attaining Jannah? 

Is what I’m doing counting as doing it for Allah’s sake because I feel unsure and don’t want to do it for the sake of gaining something and get no rewards? How can I make it so that I get rewarded and get what I want in regards to a worldly gain I want?

Keeping the head straight during qiyaam

Q: 

1. Would it be disliked if someone bowed their head till their chin touched or almost touched their upper chest, in the standing or sitting positions of the prayer (while keeping their eyes at the various sunnah positions during the prayer)? If so, for what reason would it be disliked, and when would it not be disliked? 

2. If they did this out of feeling comfortable, would it be disliked?