Method of Salaah

Q: Does recitation of الله رب العالمين (After Surah Mulk) break ones Salaah?

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?

Q: Please advise how to soften my heart. I recently cannot cry. No matter how afraid I am of my sins and meeting Allah Ta'ala, I cannot cry when making dua. If it's my medication, do I stop it? What if I battle without my medication? At the same time, I'm worried about becoming hard hearted. 

I also cannot concentrate at all in my salaah. How do I become a better Muslim?

Q: Regarding duaas in sujood, can one make any duaa in sujood or does it have to from the Quraan?

Q: 

1. During Salah, while I am reciting a surah or something else, must I stop reciting to breathe in or out through my mouth and then continue or can I keep on reciting while I take a breath? 

2. The same question as above for yawning.

Q: In Prayer behind the Imam, if the Imam starts reciting whilst one just started reading the Thana and he was in the middle of saying اللهم in the Thana but the Imam had already started so he just finished saying Allahumma then he stopped reading the Thana, 

1. Would the prayer be valid? 

2. Would he have missed a Wajib and have to repeat the salah for missing a Wajib?

Q: Is it permissible to picture that one is standing in front of the Roza-Mubarak when reciting Durood Shareef in Salaah?

Q: Can a person add Sayyiduna when reciting Durood Ebrahim in Salaah?